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Nr. 37
Mai 2012
SPG MITTEILUNGEN
COMMUNICATIONS DE LA SSP
The interesting relation between Albert
Einstein and Georges Lemaître, two pioneers of modern cosmology, is adressed in
the article "From Static to Expanding Models of the Universe" on page 43.
The location of this year's annual meeting on the
Hönggerberg Campus.
Picture © Ralph Bensberg/ETH Zürich
Im vergangenen Herbst erhielt Martin
Gutzwiller den Doktor honoris causa der
Universität Freiburg; ein willkommener Anlass für die SPG, die wissenschaftlichen
Verdienste dieses grossen Schweizer Physikers zu würdigen. Ab S. 34 berichten wir
über Gutzwillers grundlegende Arbeiten
auf den Gebieten des Quantenchaos und
der korrelierten Elektronen.
Public lectures
The program of this year's annual meeting includes two public highlights:
Nobel laureate Samuel C. C. Ting (CERN & MIT) will talk about space-borne
detectors for cosmic rays, a key technology worth mentioning at the centennial of the discovery of cosmic rays.
Gebhard F. X. Schertler (ETH Zürich & PSI) will explain in a public tutorial
about "Ultrafast Biology" (organised by NCCR MUST and ETH FAST), how
experiments at the SwissFEL will help to better understand biological processes.
Annual Meeting of the
Swiss Physical Society
June 21 - 22, 2012 , ETH Zürich
General information: page 11, preliminary program: page 15
SPG Mitteilungen Nr. 37
Inhalt - Contenu - Contents
Jahrestagung der SPG in Zürich, 21. - 22. Juni 2012 - Réunion annuelle de la SSP à Zürich, 21 - 22 juin 2012
Vorwort - Avant-propos
Preisverleihung und Generalversammlung 2012 - Cérémonie de remise des prix et assemblée générale 2012
Statistik - Statistique
Jahresbericht des Präsidenten - Rapport annuel du président
Protokoll der Generalversammlung 2011 in Lausanne - Protocole de l'assemblée générale 2011 à Lausanne
Jahresrechnung 2011 - Bilan annuel 2011
Anpassung der Statuten - Modification des statuts
Neue Sektion und Kommission - Nouvelle section et commission
Allgemeine Tagungsinformationen - Informations générales sur la réunion
Vorläufige Programmübersicht - Résumé préliminaire du programme
Aussteller - Exposants
Kurzmitteilungen
Progress in Physics (28): SATW Forum "Advanced Optoceramics"
Progress in Physics (29): Understanding exchange bias in thin films
The legacy of Martin Gutzwiller
Martin Gutzwiller and his periodic orbits
Martin Gutzwiller and his wave function
Physik und Gesellschaft: "Lead-User-Workshops" für effizientes Innovations- & Produktvariantenmanagement
History of Physics (4): From Static to Expanding Models of the Universe
Über den Einfluss des Lichtes auf den Menschen
Nicht-visuelle Lichtwirkungen beim Menschen
Lighting Application for Non-Visual Effects of Light
3
3
3
4
5
5
7
9
10
11
15
27
27
28
30
34
34
37
41
43
47
47
49
Vorstandsmitglieder der SPG / Membres du Comité de la SSP
Physikausbildung und -förderung /
Education et encouragement à la physique
Dr. Tibor Gyalog, Uni Basel, [email protected]
Präsident / Président
Dr. Christophe Rossel, IBM Rüschlikon, [email protected]
Vize-Präsident / Vice-Président
Dr. Andreas Schopper, CERN, [email protected]
Geschichte der Physik / Histoire de la Physique
Prof. Jan Lacki, Uni Genève, [email protected]
Sekretär / Secrétaire
Dr. MER Antoine Pochelon, EPFL-CRPP, [email protected]
SPG Administration / Administration de la SSP
Kassier / Trésorier
Dr. Pierangelo Gröning, EMPA Thun, [email protected]
Allgemeines Sekretariat (Mitgliederverwaltung, Webseite, Druck, Versand, Redaktion Bul/
Secrétariat générale (Service des membres, internet, impression, envoi, rédaction Bulletin
letin & SPG Mitteilungen)
Kondensierte Materie / Matière Condensée (KOND)
Dr. Urs Staub, PSI, [email protected]
& Communications de la SSP)
S. Albietz, SPG Sekretariat, Departement Physik,
Klingelbergstrasse 82, CH-4056 Basel
Tel. 061 / 267 36 86, Fax 061 / 267 37 84, [email protected]
Angewandte Physik / Physique Appliquée (ANDO)
Dr. Ivo Furno, EPFL-CRPP, [email protected]
Astrophysik, Kern- und Teilchenphysik /
Astrophysique, physique nucléaire et corp. (TASK)
Prof. Martin Pohl, Uni Genève, [email protected]
Buchhaltung / Service de la comptabilité
F. Erkadoo, SPG Sekretariat, Departement Physik,
Klingelbergstrasse 82, CH-4056 Basel
Tel. 061 / 267 37 50, Fax 061 / 267 13 49, [email protected]
Theoretische Physik / Physique Théorique (THEO)
Prof. Gian Michele Graf, ETH Zürich (ad interim), [email protected]
Sekretärin des Präsidenten / Secrétaire du président
Susanne Johner, [email protected]
Physik in der Industrie / Physique dans l‘industrie
Dr. Kai Hencken, ABB Dättwil, [email protected]
Wissenschaftlicher Redakteur/ Rédacteur scientifique
Dr. Bernhard Braunecker, Braunecker Engineering GmbH,
[email protected]
Atomphysik und Quantenoptik /
Physique Atomique et Optique Quantique
Prof. Antoine Weis, Uni Fribourg, [email protected]
Impressum:
Die SPG Mitteilungen erscheinen ca. 2-4 mal jährlich und werden an alle Mitglieder abgegeben.
Abonnement für Nichtmitglieder:
CHF 20.- pro Jahrgang (Inland; Ausland auf Anfrage), incl. Lieferung der Hefte sofort nach Erscheinen frei Haus. Bestellungen
bzw. Kündigungen jeweils zum Jahresende senden Sie bitte formlos an folgende Adresse:
Verlag und Redaktion:
Schweizerische Physikalische Gesellschaft, Klingelbergstr. 82, CH-4056 Basel, [email protected], www.sps.ch
Redaktionelle Beiträge und Inserate sind willkommen, bitte wenden Sie sich an die obige Adresse.
Namentlich gekennzeichnete Beiträge geben grundsätzlich die Meinungen der betreffenden Autoren wieder. Die SPG übernimmt hierfür keine Verantwortung.
Druck:
Werner Druck AG, Kanonengasse 32, 4001 Basel
2
Communications de la SSP No. 37
Jahrestagung der SPG in Zürich, 21. - 22. Juni 2012
Réunion annuelle de la SSP à Zürich, 21 - 22 juin 2012
Vorwort
Avant-propos
Die erfolgreichen Tagungen der letzten Jahre haben gezeigt,
daß die SPG auf dem richtigen Pfad ist. Sowohl die Beteiligung der verschiedenen NCCRs alle 2 Jahre, als auch die
Kooperation mit unseren österreichischen Nachbarn erlauben eine exzellente Vernetzung und den Austausch über
Fachbereichs- und Landesgrenzen hinweg. Nicht zuletzt
die Zusammenarbeit mit Fachgesellschaften, die einen
starken Bezug zur Physik haben, erlaubt auch immer wieder den Blick über den Tellerrand des eigenen Wirkens.
Le succès des réunions des années dernières a démontré
que la SSP est sur la bonne voie. Autant la participation des
différents NCCRs tous les deux ans que notre coopération
avec nos voisins autrichiens, favorisent le développment
d’un excellent réseau et l’échange au delà des spécialités et
des frontières. La collaboration avec les sociétés savantes
qui ont un fort lien avec la physique, permet aussi de jeter
régulièrement un coup d’oeil sur les domaines adjacents à
nos propres activités.
In diesem Jahr ist z.B. das 100jährige Jubiläum der Entdeckung der Röntgenbeugung durch Max von Laue Anlaß für
die Schweizerische Gesellschaft für Kristallographie (SGK),
sich mit einer Sitzung an unserer Tagung zu beteiligen.
Der Einbezug von lange vernachlässigten Fachgebieten ist
ebenfalls geglückt, wie z.B. die nun bereits fest etablierte
Sitzung zur Geschichte der Physik zeigt. Die letztjährige Sitzung zur Geophysik gibt sogar Anlaß, das Gebiet in diesem
Jahr in einen erweiterten Rahmen unter "Physik der Erde,
Atmosphäre und Umwelt" einzubetten und eine gleichnamige Sektion zu gründen.
Cette année, la célébration du centenaire de la découverte de la diffraction des rayons X par Max von Laue, est
l’occasion pour la Société Suisse de Crystallographie de
participer avec une session à notre réunion annuelle.
L’incorporation de domaines longtemps négligés est tout
aussi réussie, tel que le montre par ex. la session désormais solidement établie sur l’Histoire de la Physique. La
séance sur la Géophysique de l’année dernière nous a
incité à élargir le sujet vers la "Physique du Globe et de
l’Environnement", et à fonder une nouvelle section du
même nom.
Im folgenden finden Sie die wichtigsten Tagungsinformationen sowie eine vorläufige Programmübersicht. Das definitive Programm wird in Kürze auf der SPG-Webseite verfügbar sein.
Dans les pages suivantes vous trouverez les informations
essentielles sur la conférence ainsi que le programme provisoire. La version finale sera prochainement accessible sur
notre site internet.
In diesem Sinne hoffen wir auf eine rege Beteiligung an der
diesjährigen Tagung und freuen uns auf Ihren Besuch.
Nous comptons donc sur une participation active et nombreuse à notre réunion annuelle et nous réjouissons de votre visite.
Preisverleihung und Generalversammlung 2012 Cérémonie de remise des prix et assemblée générale 2012
Donnerstag 21. Juni 2012, 11:30h - Jeudi 21 juin 2012, 11:30h
ETH Zürich, Hönggerberg, Gebäude HPH, Hörsaal G 1
11:30
Preisverleihung
Cérémonie de remise des prix
11:50
Generalversammlung
Assemblée générale
2.
3.
Protokoll der Generalversammlung vom
16. Juni 2011
Kurzer Bericht des Präsidenten
Rechnung 2011, Revisorenbericht
4.
5.
6.
7.
8.
Anpassung der Statuten
Neue Sektion und Kommission
Projekte
Wahlen
Diverses
Procès-verbal de l'assemblée générale du
16 juin 2011
Bref rapport du président
Bilan 2011, rapport des vérificateurs des
comptes
Modification des statuts
Nouvelle section et commission
Projets
Elections
Divers
1.
3
SPG Mitteilungen Nr. 37
Statistik - Statistique
Neue Mitglieder 2011 Nouveaux membres en 2011
Prof. K. Alex Müller (1991)
Prof. Hans Rudolf Ott (2005)
Prof. T. Maurice Rice (2010)
Dr. Heinrich Rohrer (1990)
Prof. Louis Schlapbach (2010)
Allenspach Rolf, Ammann Stephan, Anabitarte Miguel, Andritsch Florian, Balzan Riccardo, Becker Henrik, Bednorz
J. Georg, Birrer Simon, Boillat Bénédicte, Boss Jens Michael, Bräm Beat, Braitsch Daniel, Braun Johannes, Büchel
Samuel, Bunk Oliver, Capelli Achille, Cedzich Christopher,
Chang Johan, Chopdekar Rajesh Vilas, Chowdhuri Zema,
Christandl Matthias, Ciganovic Nikola, Conrad Roberta, Dahinden Fabienne, Debus Pascal, Diebold Andreas, Donner
Tobias, Eggenschwiler Federico, Ehrbar Stefanie, El Bakkali Issam, El Moussaoui Souliman, Falke Johannes, Flöry
Nikolaus, Flühmann Christa, Gauvin Neal, Gehrig Jeffrey,
Gehrmann-De Ridder Aude, Gersdorf Thomas, Göldi Damian, Gomes Gerber Isabel, Grimm Alexander, Häberli Florian, Hälg Sebastian, Häusler Samuel, Herrmann Andreas,
Howald Ludovic, Huber Felix, Iacobucci Giuseppe, Imamoglu Atac, Jenatsch Sandra, Jochum Johanna, Jusufi Abas,
Kambly Dania, Kamleitner Josef, Kangeldi Selim, Kasprzak
Malgorzata, Keller Stefan, Khaw Kim Siang, Kläui Mathias,
Klauser Christine, Kobayashi Masaki, Korppi Maria, Koulialias Dimitrios, Krempasky Juraj, Kreslo Igor, Kwuida-Manthey Katarina, Leimer Pascal, Löffler Jörg F., Lüthi Florian,
Maetz Marc, Maghrbi Yasser, Marsik Premysl, Minkowski
Peter, Mirzaei Seyed Imam, Mokso Rajmund, Moser Christophe, Nicola Andrina, Oberle Markus, Ockeloen Caspar,
Orsi Silvio, Pagani Kurt, Papariello Luca, Parrinello Michele,
Patthey Luc, Pavuna Davor, Pfefferle David, Piamonteze
Cinthia, Pikulski Marek, Pilet Nicolas, Plumb Nicholas, Prsa
Krunoslav, Radovic Milan, Reichert Julia, Riedo Andreas,
Rocco Gaudenzi, Rodriguez Alvarez José, Rose Ruben,
Ruffieux Silvia, Rutar Giada, Schäfer Vera, Schmidt Alexander, Schnoz Sebastian, Schönherr Peggy, Schopper Andreas, Schulthess Thomas, Schumann Marc, Sehner Michael,
Seidel Mike, Sellerio Alessandro Luigi, Shiroka Toni, Stamm
Christian, Stelzer Carol, Stöckl Quirin S., Timpu Flavia
Claudia, Tortschanoff Andreas, Tschirky Thomas, Verzetti
Mauro, Viereck Julian, von Baussnern Samuel, Wacker Kay,
Wágner Dávid, Wallny Rainer, Walt Roger, Waltar Kay, Ward
Simon, Watts Benjamin, Weigele Pirmin, Wenzler Dominic,
Wertnik Melina, Winkler János, Winterhalter Carla, Wittwer
Peter, Witzemann Amadeus, Yarar Hevjin, Zai Anja
Assoziierte Mitglieder - Membres associés
A) Firmen
• F. Hoffmann-La-Roche AG, 4070 Basel
• Oerlikon Leybold Vacuum Schweiz AG, 8050 Zürich
B) Universitäten, Institute
• Albert-Einstein-Center for Fundamental Physics, Universität Bern, 3012 Bern
• Département de Physique, Université de Fribourg,
1700 Fribourg
• Departement Physik, Universität Basel, 4056 Basel
• Departement Physik, ETH Zürich, 8093 Zürich
• EMPA, 8600 Dübendorf
• Lab. de Physique des Hautes Energies (LPHE), EPFL,
1015 Lausanne
• Paul Scherrer Institut, 5332 Villigen PSI
• Physik-Institut, Universität Zürich, 8057 Zürich
• Section de Physique, Université de Genève, 1211 Genève 4
C) Studentenfachvereine
• AEP - Association des Etudiant(e)s en Physique, Université de Genève, 1211 Genève 4
• Fachschaft Physik und Astronomie, Universität Bern,
3012 Bern
• Fachschaft Physique, Université de Fribourg, 1700 Fribourg
• Fachverein Physik der Universität Zürich (FPU),
8057 Zürich
• FG 14 (Fachgruppe für Physik-, Mathematik- und Versicherungswissenschaft), Universität Basel, 4056 Basel
• Les Irrotationnels, EPFL, 1015 Lausanne
• Verein der Mathematik- und Physikstudierenden an
der ETH Zürich (VMP), 8092 Zürich
Verteilung der Mitgliedskategorien Répartition des catégories de membres
(31.12.2011)
Ehrenmitglieder - Membres d'honneur
Prof. Hans Beck (2010)
Dr. J. Georg Bednorz (2011)
Prof. Jean-Pierre Blaser (1990)
Prof. Jean-Pierre Borel (2001)
Prof. Jean-Pierre Eckmann (2011)
Prof. Charles P. Enz (2005)
Prof. Øystein Fischer (2010)
Prof. Hans Frauenfelder (2001)
Prof. Jürg Fröhlich (2011)
Prof. Hermann Grunder (2001)
Prof. Hans-Joachim Güntherodt (2010)
Dr. Martin Huber (2011)
Prof. Verena Meyer (2001)
4
Ordentliche Mitglieder
Doktoranden
Studenten
Doppelmitglieder DPG, ÖPG oder APS
Doppelmitglieder PGZ
Mitglieder auf Lebenszeit
Assoziierte Mitglieder
Bibliotheksmitglieder
Ehrenmitglieder
Beitragsfreie (Korrespondenz)
Total
697
37
78
193
38
150
16
2
18
10
1239
Communications de la SSP No. 37
Jahresbericht 2011 des Präsidenten - Rapport annuel 2011 du président
Once again, one of the highlights of 2011 for the SPS
was its successful annual meeting organized at the EPFL
in Lausanne on 15-17 June 2011, jointly with the Austrian
Physical Society (ÖPG), and both national societies of Astronomy and Astrophysics (SSAA and ÖGAA). It was very
well attended with about 650 participants, 10 plenary talks,
470 contributions spread over 10 parallel sessions and one
large poster session. The commercial exhibitions reached
a record number of 22 company booths. One can claim
without any doubt that the formula of having our meeting
every other year with our Austrian colleagues is a success.
The meeting 2013 is therefore already planned in Vienna for
early September.
The organization of the alternating meetings with the Swiss
NCCRs and other invited learned societies has also proven to be an excellent and appreciated means to make this
event attractive to the Swiss community. A detailed review
of the meeting 2011 was published in the SPS Communications No 35 and on our website.
Worth remembering is the celebration of the centennial of
the discovery of superconductivity with dedicated talks, a
lively round table in presence of the two Nobel Laureates K.
A. Müller and J. G. Bednorz and a special exhibition.
Based on the success of the session on Geophysics, it was
proposed to create a new section named "Earth, Atmosphere and Environmental Physics". A dedicated session on
this topic is planned in our next annual meeting at the ETHZ
on 21-22 June 2012 (see page 10 in this issue for details).
During the joint award ceremony the three SPS awards as
well as several prizes of the ÖPG were attributed. During
this ceremony the honorary membership was conferred to
four new members.
At the General Assembly, two new board members have
been elected; several others have been reelected (see minutes on the next page).
It is with pleasure that the SPS endorsed also the new
membership of CHIPP, the Swiss Institute of Particle Physics, presided by Martin Pohl, within SCNAT. It trusts that
this sister organization will strengthen science in general
and physics in particular in association with the SPS.
The number of individual members keeps increasing steadily with about 1250 by the end of 2011. This enjoyable trend
goes in parallel with the strong increase of collective members - renamed ‘associate’ members in the future - found
among the different departments of physics, research organizations and physics student associations.
Because of improved financial incomes (membership, exhibition) but also because of stronger control of our expenses
(reduction of publication and mailing costs) the negative
trend of the last three years has been stopped and our budget 2011 ended again in the black with a slight earning.
Thanks to the excellent work of our scientific editor B.
Braunecker, the SPS Bulletin continues to be a valuable
source of information with society news, and the now well
established topical rubriques 'Progress in Physics', 'Physics and Society' and 'Physics Anecdotes'.
In our collaboration with the Physikalische Gesellschaft Zurich (PGZ), a joint Symposium on "Careers for Physicists"
was organized on the 25 October 2011. The student associations of the SPS Young Physicists Forum (YPF), VMP
(ETHZ), FPU (Uni. Zürich) and FG14 (Uni. Basel) participated in this successful symposium. In fact the YPF remains
active and continues to organize special events, such as
visits of research centers or institutes for its student members.
In a well established tradition, the SPS sponsored also the
Swiss Physics Olympiads and the Swiss Young Physicists
Tournament in their respective activities. The best male and
female finalists of the SwissPhO were awarded with SPS
prizes (http://www.swisspho.ch/en/winners2011).
The SPS is actively represented via its president or other
members in different EPS groups and commissions, in particular the editorial board of Europhysics News, Europhysics Letters, the Forum Physics and Society, the Technology group and the Energy group. The meeting of the latter
took place at the Akershus Energy Park, close to Oslo on
6-7 October 2011. In addition to energy issues specific to
Norway (hydro-energy, Thorium reactors), reports on radioactive waste disposal techniques and the status of disposals in EU nuclear energy countries including Switzerland
(Nagra) were presented.
As a member organization of the Swiss Academy of Science SCNAT, the SPS is part of the platform Mathematics,
Astronomy and Physics. We acknowledge here the organizational and financial support of SCNAT in the pursuit of
our tasks and activities. The support of the Swiss Academy
of Engineering Science SATW is also acknowledged and
hopefully our interaction will be further developed on important issues such as energy, resources and sustainability,
information technology, nanotechnology, education as well
as the training of the physicists in industry and academia.
Christophe Rossel, President, March 2012
Protokoll der Generalversammlung vom 16.06.2011 in Lausanne
Protocole de l'assemblée générale du 16.06.2011 à Lausanne
Traktanden
1. Protokoll der Generalversammlung vom 22.6.2010
2. Bericht des Präsidenten
3. Rechnung 2010 & Revisorenbericht
4. Wahlen
5. Projekte
6. Diverses
Der Präsident, Christophe Rossel, eröffnet die Generalversammlung um 12:10 Uhr. Anwesend sind 31 Mitglieder.
1. Protokoll der Generalversammlung vom 22.6.2010
Das Protokoll der letzten Generalversammlung in Basel
wird kommentarlos genehmigt.
5
SPG Mitteilungen Nr. 37
Nachdem der Revisorenbericht vorgelesen worden ist,
stimmt die Generalversammlung der Jahresrechnung 2010
und der Entlastung des Vorstands zu.
2. Bericht des Präsidenten
Auf Seite 5 der „SPG Mitteilungen Nr. 34“ wurde der Jahresbericht des Präsidenten bereits veröffentlicht.
•Zur Jahrestagung vom 21.-22. Juni 2010 in Basel mit
NCCR ManEP, NANO, QP, CCMX, POLYCOLL (SCG) kamen rund 500 Teilnehmer und 17 Aussteller.
•An der Generalversammlung 2010 wurden fünf neue Ehrenmitglieder ernannt: Profs. H. Beck, O. Fischer, H.-J.
Güntherodt, T. M. Rice, L. Schlapbach.
•Die GV 2010 schuf neue Mitgliederkategorien und
passte sowohl die Statuten an, wie teilweise auch die
seit acht Jahren unveränderten Mitgliederbeiträge.
•Als Werbeaktion erhielten alle Schweizer Physikprofessoren den neuen SPG-Flyer zum Verteilen an die Studierenden.
•Folgende Institutionen konnten als Kollektivmitglieder
gewonnen werden: Die Physik-Departemente der Universitäten Basel, Genf und Zürich, der ETH Zürich, das
LPHE der EPF Lausanne sowie die Studentenvereine
VMP (ETHZ), FPU (Uni ZH), AEP (Uni Genf).
Der Präsident informiert die Anwesenden, dass der Vorstand die missverständliche Bezeichnung "Kollektivmitgliedschaft" durch "Assoziierte Mitgliedschaft" ersetzen
möchte. Die erforderliche Statutenänderung wird nächstes Jahr auf die Traktandenliste gesetzt und der GV
2012 zur Abstimmung vorgelegt.
•Die dreimal jährlich erscheinenden "SPG Mitteilungen"
werden noch interessanter: Zu den bisherigen Rubriken
"Fortschritt in der Physik", "Physik & Gesellschaft" und
"Physik-Anekdoten" kommt die neue Serie "Geschichte
der Physik".
4. Wahlen
Der Präsident dankt den beiden ausscheidenden Vorstandsmitgliedern für ihren Einsatz: Prof. Klaus Kirch, 6
Jahre Leiter der SPG-Sektion "Astro-, Kern- Teilchenphysik" und Prof. Ulrich Straumann, 2 Jahre Vize-Präsident der
SPG.
In corpore werden einstimmig neu resp. wieder gewählt:
•Vize-Präsident (neu): Dr. Andreas Schopper, CERN
•Astro-, Kern- Teilchenphysik (neu): Prof. Martin Pohl,
Universität Genf
•Atomphysik & Quantenoptik (bisher): Prof. Antoine Weis,
Universität Fribourg
•Physik in der Industrie (bisher): Dr. Kai Hencken, ABB
•Theoretische Physik (bisher): Prof. Dionys Baeriswyl,
Universität Fribourg
• Angewandte Physik (bisher): Dr. Ivo Furno, EPFL
•Physikausbildung & -förderung (bisher): Dr. Tibor Gyalog, Universität Basel
5. Projekte
•Das "Young Physicists Forum" wird mit den StudentenFachschaften weitere Aktivitäten, Betriebsbesichtigungen und Exkursionen für Studenten organisieren.
•Zusammen mit dem PGZ plant die SPG im September
2011 in Zürich ein Symposium über den Physiker-Beruf.
6. Diverses
•An der letzten GV wünschte ein Mitglied, die SPG solle
dem Anglizismus entgegentreten und dafür sorgen, dass
vermehrt deutschsprachige Beiträge gedruckt werden.
Der Vorstand hat das Anliegen diskutiert, sieht jedoch
keinen Handlungsbedarf. Bei einem Mitgliedermagazin
wie den "SPG Mitteilungen" muss in erster Linie der
Inhalt stimmen – in welcher Sprache ist weniger wichtig. Was andere Publikationen betrifft, kann und will der
SPG-Vorstand keinen Einfluss auf redaktionelle Entscheide nehmen.
• Die nächste SPG-Jahrestagung wird am 21./22. Juni
2012 an der ETH Zürich stattfinden. Weitere Einzelheiten
erscheinen demnächst auf der SPG-Internetseite (www.
sps.ch).
Besondere Anlässe im vergangenen Vereinsjahr waren:
•Öffentlicher, von SPS und PGZ gemeinsam organisierter
Anlass "DIE WISSENSEXPLOSION – Chancen und Risiken – Wissenschaftskommunikation im Zeitalter elektronischer Medien", Sa. 02.10.2010, Uni Zürich.
•50 Jahre Laser: Der Tanz der Photonen, vom 10.12.06.2010 an der Universität Bern und vom 19.20.11.2010 an der Universität Fribourg.
•Im Rahmen unseres neuen Young Physicists Forums
(VMP) organisierte der VMP (Verein Mathematik- &
Physik-Studierender der ETH Zürich) folgende gut besuchte Exkursionen: PSI Villigen (4.5.2010), EPFL-CRPP
(22.11.2010), ABB (18.4.2011) und IBM Research
(30.5.2011).
•Als Sponsor der Schweiz. Physik-Olympiaden stiftet die
SPG jeweils zwei Nachwuchspreise zu je CHF 500, welche der Präsident an der Schlussfeier vom 3.4.2011 in
Aarau überreichte.
•Weiterhin ist die SPG Sponsor des Swiss Young Physicists Tournament (PSI, April 2011) und des Schweizer
Teams am International Young Physicists Tournament
(Teheran, Juli 2011).
Der Präsident dankt den Anwesenden für ihr Erscheinen
sowie den Delegierten und seinen Vorstandskollegen für Ihren Einsatz und die gute Zusammenarbeit im vergangenen
Amtsjahr.
Ende der Generalversammlung: 11:15 Uhr.
Lausanne, 16. Juni 2011
Die Protokollführerin: Susanne Johner
3. Rechnung 2010 & Revisorenbericht
Der Kassier, Pierangelo Gröning, präsentiert die Jahresrechnung 2010, die detailliert in den "SPG-Mitteilungen Nr.
34" veröffentlicht wurde. Sie schliesst mit einem Verlust von
CHF 25'777, bei einem Vereinsvermögen per 31.12.2010
von CHF 19'406.50.
6
Communications de la SSP No. 37
Jahresrechnung 2011 - Bilan annuel 2011
Bilanz per 31.12.2011
Aktiven
Umlaufsvermögen
Postscheckkonto
Bank - UBS 230-627945.M1U
Debitoren - Mitglieder
Debitoren - SCNAT/SATW u.a.m.
Transitorische Aktiven
Passiven
19233,53
12575,54
2017,50
56851,00
1049,70
Anlagevermögen
Beteiligung EP Letters
Mobilien
15840,00
1,00
Fremdkapital
Mobiliar
Mitglieder Lebenszeit
Transitorische Passiven
1,00
59824,50
11135,90
Eigenkapital
Verfügbares Vermögen
19406,51
Total Aktiven Passiven
Gewinn
Total
107568,27
107568,27
Verfügbares Vermögen per 31.12.11 nach Gewinnzuweisung
90367,91
17200,36
107568,27
36606,87
Erfolgsrechnung per 31.12.2011
Aufwand
Gesellschaftsaufwand
EPS - Membership
SCNAT - Membership
SATW-Mitgliederbeitrag
Ertrag
15634,30
7903,00
1750,00
SCNAT & SATW Verpflichtungskredite
SPG-Jahrestagung
Schweizer Physik Olympiade
SPG Young Physicist's Forum
EGA-43 Kongress 2011, Fribourg
100 Jahre Supraleitung
SCNAT/SPG Bulletin
SCNAT Periodika (SPG-Mitteilungen, Druckkosten)
SCNAT Int. Young Phys. Tournament
37766,26
4000,00
7133,15
4000,00
11851,00
5500,00
19444,20
5500,00
Betriebsaufwand
Löhne
Sozialleistungen
Porti/Telefonspesen/WWW- und PC-Spesen
Versand (Porti Massensendungen)
Unkosten
Büromaterial
Bankspesen
Debitorenverluste Mitglieder
Debitorenverlust SCNAT/SATW u.a.m.
Sekretariatsaufwand extern
11732,64
863,25
908,75
5334,00
3130,30
321,60
163,00
1971,00
5149,00
9675,00
Ertrag
Mitgliederbeiträge
Inserate/Flyerbeilagen SPG Mitteilungen
Aussteller
Zinsertrag
Ertrag aus EP Letters Beteiligung
87670,35
200,00
24771,69
125,90
2162,87
SCNAT & SATW Verpflichtungskredite
SPG-Jahrestagung (SCNAT)
Schweizer Physik Olympiade
SPG Young Physicist's Forum
EGAS-43 Kongress 2011, Fribourg
100 Jahre Supraleitung
SATW, 100 Jahre Tieftemperatur und Supraleitung/Session Géophysique
SPG Bulletin (SCNAT)
Periodika (SPG-Mitteilungen, Druckkosten) (SCNAT)
SCNAT Int. Young Phys. Tournament
15000,00
4000,00
7000,00
4000,00
12000,00
5000,00
5500,00
4000,00
5500,00
Total Aufwand/Ertrag
Gewinn
Total
159730,45
17200,36
176930,81
7
176930,81
176930,81
SPG Mitteilungen Nr. 37
Revisorenbericht zur Jahresrechnung 2011
Die Jahresrechnung 2011 der SPG wurde von den unterzeichneten Revisoren geprüft und
mit den Belegen in Übereinstimmung befunden.
Die Revisoren empfehlen der Generalversammlung der SPG, die Jahresrechnung zu
genehmigen und den Kassier mit bestem Dank für die gute Rechnungsführung zu
entlasten.
Die Revisoren der SPG:
Prof. Dr. Philipp Aebi
Dr. Pascal Ruffieux
Basel, 15. März 2012
F. Erkadoo, SPG Büro, Departement Physik, Klingelbergstrasse 82, CH-4056 Basel
Tel : 061 / 267 37 50, Fax : 061 / 267 13 49, Email : [email protected]
8
Communications de la SSP No. 37
Anpassung der Statuten - Modification des statuts
Seit der letzten Änderung vor zwei Jahren ist der Vorstand
auf zwei kleine Unschönheiten in den Statuten aufmerksam
gemacht worden. Diese betreffen den Begriff "Kollektivmitglieder", der verschiedentlich zu Mißverständnissen geführt
hat. Ferner wird die Definition der Kollektivmitglieder Gruppe B als zu eng gefasst angesehen, da z.B. eine überstaatliche Organisation wie das CERN danach nicht Mitglied
werden kann.
Après les dernières modifications d'il y a deux ans, le comité a été rendu attentif à deux petites imprécisions dans
les statuts. Elles concernent le terme de 'membre collectif'
qui a conduit à quelques malentendus. De plus la définition
du groupe B des membres collectifs est considérée comme
trop limitée. Ainsi une organisation internationale comme le
CERN ne pourrait pas devenir membre de la SSP.
Pour ces raisons il sera nécéssaire de se prononcer sur les
petits amendements suivants:
-le terme "membres collectifs" est remplacé par "membres associés" dans les Article 2 et Annexe 1.
-la définition du groupe B dans l'Article 2 est élargie.
La version actuelle des statuts se trouve sous www.sps.ch
-> SSP -> Statuts.
Es wird daher über die folgenden kleinen Änderungen abgestimmt:
- Der Begriff "Kollektivmitglieder" wird ersetzt durch "Assoziierte Mitglieder". Dies betrifft Artikel 2 und Anhang 1.
- Die Definition der Gruppe B in Artikel 2 wird erweitert.
Die bisherige Fassung der Statuten finden Sie auf www.
sps.ch ->SPG ->Statuten.
Art. 2
Die Gesellschaft besteht aus ordentlichen Mitgliedern, aus
studentischen Mitgliedern (Studenten), aus Ehrenmitgliedern und aus Assoziierten Mitgliedern.
Als Studenten gelten Personen, welche an einer Universität immatrikuliert sind und noch keinen Diplom-/Masterabschluß haben.
Assoziierte Mitglieder werden in folgende Gruppen eingeteilt:
A)Firmen
B)Universitäten bzw. deren Untereinheiten (z.B. Institute, Forschungslabore) oder anerkannte staatliche,
überstaatliche bzw. internationale Forschungseinrichtungen
C)Studentenorganisationen / Fachgruppen an Schweizer Hochschulen
[...]
Art. 2
La Société se compose de membres ordinaires, de membres
étudiants, de membres honoraires et de membres associés.
Comme étudiants sont considérées les personnes immatriculées dans une université et qui n’ont pas encore obtenu
de Diplôme ou Master.
Les membres associés se composent des groupes suivants:
A)Compagnies commerciales
B)Universités et leurs unités (par ex. instituts, laboratoires
de recherche) ainsi que les institutions nationales, supranationales ou internationales de recherche.
C)Organisations ou associations d’étudiants liées à une
université suisse
[...]
Art. 24
Die gegenwärtige Version der Statuten der Schweizerischen Physikalischen Gesellschaft wurde an der Generalversammlung vom 21. Juni 2012 in Zürich angenommen.
Sie annulliert alle vorherigen Bestimmungen.
Art. 24
La présente version des statuts de la Société Suisse de
Physique a été adoptée par l’assemblée générale à Zürich,
le 21 juin 2012. Elle annule toutes les dispositions antérieures.
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Visit
our booth
at the Annual
Meeting,
21–22 June
SPG Mitteilungen Nr. 37
New Section "Earth, Atmosphere and Environmental Physics"
Neue Sektion "Physik der Erde, Atmosphäre und Umwelt"
Nouvelle section "Physique du Globe et de l’Environnement"
In 2012, the SPS starts up a new section, Earth, Atmosphere and Environmental Physics, following formally the
2011 sessions on geophysics (From Planetary to Engineering Geophysics).
rays, extra-terrestrial geophysics,…) to engineering geophysics, applied geophysics (analysis of geological resources, of geomaterials, of geological hazards, of geological
barriers for waste storage, monitoring of contaminated
sites), aiming at a description from first principles.
Earth, atmosphere and environmental physics can be described in terms of the laws of physics. Examples include
a number of environmental issues such as global warming,
waste depositories, ozone layer depletion, energy crisis and
renewable energy sources, air, soil and water pollution, etc.
This section pays tribute to the emphasis placed on monitoring and understanding processes, as well as predicting
changes of our physical world. The underlying topics may
be regarded as Earth- or geo-sciences oriented, being a
particular combination of physical, chemical, and biological processes linking and determining every components of
the Earth system on a wide variety of spatial and temporal
scales.
Atmospheric Physics is concerned with the structure and
evolution of the planetary atmospheres and with the wide
range of phenomena that occur within them, with a particular focus on the Earth’s atmosphere interacting with other
components such as the lithosphere, the biosphere, the hydrosphere and the cryosphere.
Environmental Physics involves the many aspects of physics that pervade environmental processes in our everyday
lives and in naturally occurring phenomena. This includes
energy supply and resources issues, which growing needs
and use can impact on environment. It aims at understanding the various links between topics such as, e.g.: sustainability, contribution of renewable sources, efficiency,
wastes and pollution, CO2, climatic impact.
Earth Physics encompasses a number of topics from the
geophysics of the globe (plate tectonics, geomagnetism,
solid state at high pressures, seismology, geodesy, cosmic
New Commission "Young Physicists Forum"
Until now, the Young Physicists Forum (YPF) is a loose
compound of nearly all Swiss physics students organizations – namely the associations from École polytechnique
fédérale de Lausanne, ETH Zürich, Uni Basel, Uni Bern, Uni
Fribourg and Uni Genève.
tation with the board of the SPS we think that all involved
parties can profit if the YPF is formaly founded as a commission of the SPS.
In a first step all participating students organizations joined
the SPS as Associated Members. The next step is our formal application at the General Assembly at the SPS annual
meeting in June 2012, to accept the YPF as a commission.
If our inquiry is accepted, we see it as our responsibility to
bring our students in contact with the SPS so they get an
impression of the wide range of possibilities they will have
when finishing their studies. Thus we want to spark interest
of young physics students in the SPS as soon as possible.
We are looking forward to a productive and successful cooperation and many new acquaintances.
Everything started at our first meeting in May 2011, where
the representatives of the different students organizations
agreed on the fact that there is a need for better connection
amongst the physics students and between students and
experienced physicists. To work out our aims and goals
more precisely we started to meet regularly, each semester at a different university, to force initially the exchange
amongst our board members. Since our first meeting the
SPS supported us and offered their help.
List of YPF founding members:
Les Irrotationnels, Association des étudiants en physique
de l'EPFL, http://irrotationnels.epfl.ch
Verein der Mathematik- und Physikstudierenden an der
ETH Zürich (VMP), www.vmp.ethz.ch
Uni Basel, Fachgruppe 14 (FG 14), www.fg14.unibas.ch
Uni Bern, Fachschaft Physik und Astronomie (FPA), http://
www.fpa.unibe.ch
Uni Fribourg, Fachschaft Physique (FPF)
Uni Genève, Association des Etudiant(e)s en Physique
(AEP), http://www.asso-etud.unige.ch/aep/
As a result of our efforts, the main goal of the YPF is to build
up a network and encourage the exchange of information
and experience amongst our students, but also with other
physicists. This we want to reach e.g. by organizing joint
events like visits of research institutions, companies etc.
Starting to include the members of our associations, our
web-forum was released in April 2012 and as a first event
we plan to visit CERN this summer. To foster the communication between our members and "real-life physicists" the
SPS turns out to be the ideal platform as they already combine reasearch and industrial interests, covering all areas
of physics. In addition the SPS offers a stable framework
within which the YPF can develop and grow. After consul-
Julia Reichert and Talitha Weiss, YPF, Universität Basel
10
Communications de la SSP No. 37
Allgemeine Tagungsinformationen - Informations générales sur la réunion
Konferenzwebseite und Anmeldung
Alle Teilnehmeranmeldungen werden über die Konferenzwebseite vorgenommen.
www.sps.ch -> Veranstaltungen
Site web de la conférence et inscription
L' inscription des participants se fait sur le site web de
la conférence.
www.sps.ch -> Evènements
Anmeldeschluß: 1. Juni 2012
Délai d'inscription: 1er juin 2012
Tagungsort
ETH Zürich, Hönggerberg, Gebäude HPH / HCI
Lieu de la conférence
ETH Zürich, Hönggerberg, bâtiment HPH / HCI
Tagungssekretariat
Das Tagungssekretariat befindet sich im Foyer des HPH
direkt neben dem Haupteingang.
Öffnungszeiten:
Mittwoch 20. Juni
16:00 - 19:00
Donnerstag 21. Juni
08:00 - 18:00
Freitag 22. Juni
08:00 - 15:00
Secrétariat de la conférence
Le secrétariat de la réunion se trouve dans le foyer du
bâtiment HPH juste à l'entrée.
Heures d'ouverture :
Mercredi 20 juin
16:00 - 19:00
Jeudi 21 juin
08:00 - 18:00
Vendredi 22 juin
08:00 - 15:00
Alle Tagungsteilnehmer melden sich bitte vor dem Besuch der ersten Veranstaltung beim Sekretariat an, wo
Sie ein Namensschild und allfällige weitere Unterlagen
erhalten sowie die Tagungsgebühr bezahlen.
Wichtig: Ohne Namensschild ist kein Zutritt zu einer
Veranstaltung möglich.
Tous les participants doivent se présenter en premier
lieu au secrétariat de la conférence afin de recevoir leur
badge et les divers documents ainsi que pour le paiement des frais d'inscription.
Attention: Sans badge, l'accès aux sessions de la manifestation sera refusé.
Wir empfehlen Ihnen, wenn möglich den Mittwoch
Nachmittag für die Anmeldung zu nutzen. So können
Sie am Donnerstag direkt ohne Wartezeiten die Vorträge
besuchen.
Nous vous recommandons de vous inscrire déjà mercredi après-midi afin d'éviter des temps d'attente inutiles jeudi matin.
Achtung: Das Tagungssekretariat gibt kein technisches
oder Büromaterial ab. Jeder Teilnehmer ist für seine
Ausrüstung (Mobilrechner, Laserpointer, Adapter, Schere, Reissnägel, Folien usw.) selber verantwortlich !
Attention: Le secrétariat de la conférence ne rend aucun matériel technique ni matériel de bureau. Chaque
participant est responsable de son équipement (ordinateur, pointeur laser, adaptateurs, ciseaux, punaises, ...) !
Hörsäle
In allen Hörsälen stehen Beamer und Hellraumprojektoren zur Verfügung. Bitte bringen Sie Ihre eigenen Mobilrechner und evtl. Adapter und USB Stick/CD mit.
Auditoires
Les auditoires disposent tous d’un projecteur multimédia (beamer) et d'un projecteur pour transparents.
Veuillez apporter votre ordinateur portable ainsi que
d'éventuels accessoires tels que clé USB ou CD.
Postersession
Die Postersession findet am Donnerstag Abend und
am Freitag während der Mittagspause im Foyer HPH
statt. Bitte bringen Sie Befestigungsmaterial (Reissnägel, Klebestreifen) selbst mit. Die Posterwände sind
entsprechend diesem Programm numeriert, sodaß jeder
Teilnehmer "seine" Wand leicht finden sollte. Alle Poster
sollen an beiden Tagen präsentiert werden.
Maximale Postergröße: A0 Hochformat
Séance posters
Les posters seront présentés dans le foyer HPH le jeudi
soir et pendant la pause de midi de vendredi. Veuillez
amener vous-même le matériel nécessaire pour fixer
les posters (punaises, ruban adhésif). Les panneaux de
posters seront numérotés suivant le numéro de l'abstract indiqué dans le programme. Tous les posters pourront rester installés pendant les deux jours.
Dimension maximale: A0, format portrait
Zahlung
Wir bitten Sie, die Tagungsgebühren im Voraus zu bezahlen. Sie verkürzen damit die Wartezeiten am Tagungssekretariat, erleichtern uns die Arbeit und sparen
darüber hinaus noch Geld !
Sie können auf das folgende Konto einzahlen / überweisen:
Postkonto der Schweizerischen Physikalischen
Gesellschaft, CH-4056 Basel,
Kontonummer 80-8738-5
Paiement
Nous vous prions de régler d'avance vos frais d'inscription par virement postal ou bancaire. De cette manière
vous éviterez des files d'attente et vous nous facilitez
notre travail. En plus vous pourrez faire des économies !
Vous pouvez effectuer votre virement sur le compte suivant:
Compte postale de la Société Suisse de Physique, CH-4056 Basel,
Numéro 80-8738-5
11
SPG Mitteilungen Nr. 37
Für Zahlungen aus dem Ausland verwenden Sie
bitte folgende Angaben:
IBAN: CH59 0900 0000 8000 8738 5
SWIFT/BIC: POFI CH BE XXX
Pour des paiements en provenance de l'étranger
veuillez utiliser les données suivantes:
IBAN: CH59 0900 0000 8000 8738 5
SWIFT/BIC: POFI CH BE XXX
Bitte achten Sie darauf, daß Ihr Name und der Zahlungszweck angegeben werden. (Es reicht nicht, wenn als Absender beispielsweise nur "Uni Basel" erscheint, da wir
eine solch allgemeine Angabe nicht einer Einzelperson
zuordnen können.)
N'oubliez pas d'indiquer votre nom et le motif de votre
paiement (la mention "Uni Bâle", par exemple, est trop
générale et ne suffit pas à identifier l'auteur du virement.)
Les paiements lors de la conférence ne pourront être
effectués qu'en espèces (CHF). Les cartes de crédit ne
pourront malheureusement pas être acceptées.
Am Tagungssekretariat kann nur bar bezahlt werden (in
CHF). Kreditkarten können leider nicht akzeptiert werden.
ATTENTION: Les frais d'inscription ne pourront pas être
remboursés.
ACHTUNG: Tagungsgebühren können nicht zurückerstattet werden.
Preise gültig bei Zahlung bis 1. Juni - Prix valable pour des paiements avant le 1er juin
Kategorie - Catégorie
CHF
SPG-Mitglieder, Doktoranden - Membres de la SSP, Doctorants
100.-
Studenten VOR Master/Diplom Abschluß - Etudiants AVANT le degré master/diplôme
30.-
Plenar-/Eingeladene Sprecher, Preisträger - Conférenciers pléniers / invités, lauréats
0.-
Andere Teilnehmer - Autres participants
140.-
Spezialangebot für "Noch-nicht-SPG-Mitglieder" (s.u.) - Offre spéciale pour "Non-membres de la SSP" (voir
ci-dessous.)
150.-
Grillparty
90.-
Zuschlag für Zahlungen nach dem 1. Juni sowie Barzahler an der Tagung Supplément pour paiements effectués après le 1er juin et pour paiements en espèces à la conférence
20.-
Kaffeepausen, Mittagessen
Die Kaffeepausen, der zur Postersitzung gehörende
Apéro am Donnerstag Abend sowie das Lunchbuffet am
Freitag finden in Foyer HPH bei der Poster- und Händlerausstellung statt. Diese Leistungen sind in der Konferenzgebühr enthalten.
Für das Mittagessen am Donnerstag stehen die Mensen
auf dem Campus Hönggerberg zur Verfügung (www.
gastro.ethz.ch).
Pauses café, repas de midi
Les pauses café, l'apéro accompagnant la séance
posters du jeudi soir et le buffet de midi du vendredi
se dérouleront dans le foyer HPH près des posters et
exposants. Ces prestations sont inclues dans les frais
d'inscription.
Pour le repas de midi du jeudi les restaurants du campus Hönggerberg sont à votre disposition (www.gastro.
ethz.ch).
Grillparty
Die Grillparty findet am Donnerstag im Anschluß an die
Postersession statt. Der Preis beträgt CHF 90.- pro Person (beinhaltet Essen und Getränke) Bitte registrieren
Sie sich unbedingt im Voraus, damit wir disponieren
können. Eine Anmeldung vor Ort ist nicht möglich !
Grillparty
La grillparty se tiendra le jeudi soir après la séance posters. Le prix est de CHF 90.- par personne (repas et
boissons inclus). Veuillez s.v.p. absolument vous enregistrer d'avance pour des raisons d'organisation. Il n'est
plus possible de s'inscrire sur place.
Spezialangebot für "Noch-Nicht" SPG-Mitglieder
Planen Sie, an unserer Tagung teilzunehmen sowie Mitglied der SPG zu werden ? Sie können nun beides für
einen äusserst günstigen Preis von nur CHF 150.- (CHF
170.- nach dem 1. Juni). Dieser Betrag deckt die Konferenzgebühr sowie die Mitgliedschaft für 2012. Verpassen Sie dieses Angebot nicht ! Wählen Sie einfach bei
der Online Registrierung die Kategorie "Special Offer",
laden Sie das Anmeldeformular ( http://www.sps.ch/
uploads/media/anmeldeformular_d-f-e.pdf ) für neue
Mitglieder herunter, drucken es aus und schicken oder
faxen es ausgefüllt an das SPG-Sekretariat.
Offre spéciale pour les non-membres de la SSP
Voulez-vous participer à la conférence et devenir aussi membre de la SSP ? Profitez de notre offre avantageuse ! Pour la somme de CHF 150.- (CHF 170.- après
le 1er juin) nous vous offrons l’inscription ainsi que la cotisation de membre de la SSP jusqu’à fin 2012. Ne ratez
pas cette occasion! Cochez simplement la case « Special Offer » lors de votre inscription en ligne, téléchargez
le formulaire d’admission à la SSP de http://www.sps.
ch/uploads/media/anmeldeformular_d-f-e.pdf , imprimez-le, et renvoyez-le dûment rempli par courrier ou par
fax au secrétariat de la SSP.
12
Communications de la SSP No. 37
(Dieses Angebot gilt nicht für Studenten oder Doktoranden. Diese profitieren sowieso von der Gratis-Mitgliedschaft im ersten Mitgliedsjahr, und zahlen nur die in der
Tabelle angegebene Konferenzgebühr.)
(Cette offre n’est pas valable pour les étudiants et les
doctorants. Ceux-ci profitent en effet d’une affiliation
gratuite à la SSP pendant la première année, et ne
paient que les frais d’inscription indiqués dans le tableau
ci-dessus.)
Hotels
Hotelreservierungen können direkt über Zürich Tourismus (www.zuerich.com) vorgenommen werden.
Hôtels
Les réservations d'hôtel peuvent être effectuées sur la
page internet de Zürich Tourisme (www.zuerich.com).
Anreise
Unter http://www.ethz.ch/about/location/hoengg finden
Sie ausführliche Hinweise zur Anreise mit verschiedenen
Verkehrsmitteln. Auf dem Campus folgen Sie einfach
den Hinweisschildern.
Arrivée
http://www.ethz.ch/about/location/hoengg/index_EN
vous donne les informations détaillées sur l'arrivée avec
les différents moyens de transport. Au campus veuillez
suivre les panneaux de la conférence.
13
SPG Mitteilungen Nr. 37
ETH Zürich – Standort Hönggerberg (Campus Science City)
B
n
aue
Sch
A
C
D
g
ber
sse
stra
en
ubt
sse
a
str
Gla
37/80
Schafmattstrasse
P
P
Conference
Parking entry
ra
einst
sse
sse
tra
i-S
löt
il-K
Em
Wolfgang-Pauli-Strasse
Einst
37/69/80
Bushaltestelle
ETH-Pendelbus «Science City Link»
Mensa
Cafeteria
Science City Welcome Desk (Telefon +041 44 633 64 44)
Alle Gebäude und Parkgaragen sind rollstuhlgängig. Weitere Informationen am Science City Welcome Desk.
Herausgeberin: ETH Zürich, Hochschulkommunikation, Mai 2011
Kartenmaterial: Institut für Kartographie der ETH Zürich, bearbeitet von Immobilien,
Stab Portfoliomanagement und Hochschulkommunikation
14
Communications de la SSP No. 37
Vorläufige Programmübersicht - Résumé préliminaire du programme
Das vollständige Programm wird allen Teilnehmern am Tagungssekretariat abgegeben sowie auf der SPG-Webseite
publiziert.
Hinweise:
- Je Beitrag wird nur der präsentierende Autor aufgeführt.
- Die Postersitzung ist am Donnerstag von 18:30 - ca.
20:00 (mit Apéro) sowie am Freitag von 12:00 - 13:30
(mit Lunchbuffet)
- (p) = Plenarsprecher, (i) = eingeladener Sprecher
Le programme final complet sera distribué aux participants
au stand du secrétariat de la conférence et sera publié sur
le site de la SSP.
Indication:
- seul le nom de l’auteur présentant la contribution a été
indiqué.
- la session poster a lieu le jeudo de 18.30 à env. 20.00
(avec apéro) ainsi que le vendredi de 12:00 à 13:30
(avec buffet de midi)
- (p) = orateur de la session plénière, (i) = orateur invité
Plenary Session
Friday, 22.06.2012, HPH G 2
Thursday, 21.06.2012, HPH G 1
Time
ID
08:55
Plenary Session I
Chair: Christophe Rossel, IBM Rüschlikon
Time
ID
Public Tutorial of NCCR MUST and ETH FAST
Chair: Ursula Keller, ETH Zürich
12:15
12
Ultrafast Biology
Gebhard F. X. Schertler, ETH Zürich & PSI Villigen (p)
Welcome note of the SPS President
09:00
1
From the QHE to Topological Insulators and on to
Cosmic Magnetic Fields - a Unified Perspective
Jürg Fröhlich, ETH Zürich (p)
09:40
2
Quantum physics in one dimension
Thierry Giamarchi, Uni Genève (p)
10:20
13:00
Special: Careers for Physicists
Coffee Break
This session is organised in conjunction
with the Physikalische Gesellschaft Zürich (PGZ).
Chair: Gervais Chapuis, EPFL
10:50
3
From Laue's discovery and the Braggs' key to the
world of atoms to service crystallography
Dieter Schwarzenbach, EPFL (p)
11:30
Award Ceremony
11:50
SPS General Assembly
12:30
Lunch
13:30
Topical Sessions
18:30
Postersession and Apéro
20:15
Grillparty
Thursday, 21.06.2012, HPH G 2
Thursday, 21.06.2012, HPH G 1
Time
ID
19:00
11
20:15
END
Public Lecture
Chair: Martin Pohl, Uni Genève
Space-borne Cosmic Ray Detectors
Samuel C. C. Ting, CERN & MIT (p)
Time
ID
Careers for Physicists
Chair: Kai Hencken, ABB Baden
13:30
31
Sensirion: High-Tech Sensors from the Zürichsee
Marc von Waldkirch (i)
14:00
32
Physicists in research administration
Florian Weissbach (i)
14:30
33
Theoretical Physics in Industrial Corporate Research
Thomas Christen (i)
15:00
34
Mesa Imaging: Seeing the world in three dimensions
Thierry Oggier (i)
15:30
END, Coffee Break
18:30
Postersession and Apéro
END
Friday, 22.06.2012, HPH G 1
Time
ID
Plenary Session II
Chair: NN
09:00
4
Nanomechanical Resonators - coherent control of
nanomechanical motion
Jörg Peter Kotthaus, LMU München (p)
09:40
5
Special: Teacher's Afternoon:
"Nanophysik am Gymnasium"
Friday, 22.06.2012, HCI D 2
Time
ID
"Nanophysik am Gymnasium"
Chair: Tibor Gyalog, Uni Basel
Charge, Spin And Structural Dynamics of molecular
systems: ultrafast optical and X-ray studies
Majed Chergui, EPFL (p)
14:30
41
Nano 4 schools - Erfahrungsbericht über 9 Jahre
Nano für Schulen
Martin Vonlanthen (i)
10:20
Coffee Break
14:50
42
11:00
Topical Sessions
Der Nanotruck in Deutschland – Eine Erfolgsstory
Andreas Jungbluth (i)
12:00
Postersession (continued), Lunchbuffet
15:10
43
13:30
Topical Sessions
Swiss nano Cube - Plattform für Wissen & Bildung
zu Nanotechnologien
Robert Rekece (i)
15:30
15
Coffee Break
SPG Mitteilungen Nr. 37
Time
ID
16:00
44
Chair: Tibor Gyalog, Uni Basel
Graetzelzellen für die Schule
Thilo Glatzel (i)
ID
100 Years of Diffraction Poster
71
A moment in time: 100 years of X-Ray diffraction versus 100
days of PHOTON 100 CMOS detector
Eric Hovestreydt
16:20
45
Nanomedizin – Eine Debatte über Technologiefolgen
Meret Hornstein (i)
16:40
46
Nano-Experimentier-Systeme für die Schule
Andreas Vaterlaus (i)
72
Ab-initio crystal structure prediction. Metal borohydrides
Riccarda Caputo
17:00
47
War Benjamin Franklin der erste Nanophysiker?
Danilo Pescia
73
Pressure modulated proton-phonon coupling and its
relevance to ceramic fuel cell proton conductors
Qianli Chen
74
Mixed-metal precursors for mixed-metal oxides
Claire-Lise Chanez
75
New penta-coordinate iron(III) aryloxide as initiators for
ring-opening polymerization
Yvens Chérémond
76
Light-induced low-spin structure of the bistable [Fe(bbtr)3]
(BF4)2 compound
Laure Guenee
77
Magnetic ground state and 2D behavior in the pseudoKagomè layered system Cu3Bi(SeO3)2O2Br
Oksana Zaharko
78
XRD investigations on PZT layers for actuator systems
Olha Sereda
79
Novel trimetallic borohydrides
Pascal Schouwink
80
TIPSI hybrid spectrometer at the European Spallation
Neutron Source ESS: Probing multiple length scales in one
instrument
Nadir Aliouane
81
Neutron diffraction and Oxygen Isotope Back Exchange
studies in La2-xSrxCuO4± (x = 0, 0.05, 0.15) crystals as a
function of temperature
Ravi Sura
82
Our fascination with crystals and crystallography – a 7500
year timeline
Rangana Warshamanage
17:20
END
Special:
A. 100 Years of Diffraction: Historical highlights and a
look into the next 100 years
This session is organised by the Swiss Society for Crystallography (SGK).
Part I is jointly organised with the SPS History of Physics section.
Thursday, 21.06.2012, HCI J 6
Time
ID
I. 100 Years of Diffraction
Chair: Jan Lacki, Uni Genève
Anthony Linden, Uni Zürich
11:50
SGK General Assembly
12:30
Lunch
13:30
51
The two Braggs
A. Michael Glazer (i)
14:00
52
Max von Laue: the physicist and the upright man
Jost Lemmerich (i)
14:30
53
The origins and development of macromolecular
crystallography
Larry Falvello (i)
15:00
54
15:30
Johannes Martin Bijvoet (1892-1980) and absolute
structure
Ton Spek (i)
Coffee Break
II. The Next 100 Years
Chair: Michael Wörle, ETH Zürich
16:00
61
Novel structural studies with an X-ray Free Electron
Laser
Bruce Patterson (i)
16:25
62
Investigating disorder as a matter of routine - the
next steps
Thomas Weber (i)
16:50
63
The Materials Science Beamline upgrade
Philip Willmott (i)
17:15
64
High Resolution X-Ray Diffraction applications for
microsystems
Antonia Neels
17:30
17:45
65
66
B. History of Physics
Thursday, 21.06.2012, HCI D 2
Powder Charge Flipping – input parameter optimization and solution evaluation
Dubravka Šišak
Time
ID
History of Physics
Chair: NN
14:30
91
The method of Victor F. Hess, or how the residual
leaking away of electric charge, a tenacious ‘shelf
warmer‘, opened up new fascinating fields of physical knowledge
Peter Schuster (i)
15:00
92
From thunderstorms to cosmic rays: Albert Gockel’s investigations in atmospheric physics
Jan Lacki
15:30
Coffee Break
Chair: NN
Intercluster compounds for nanosized materials
Fabienne Gschwind
16:00
93
The origins and fate of technical physics in
Lausanne: the creation of the Ecole Spéciale.
Régis Catinaud
16:30
94
Who discovered the Proca equation ? Lanczos, Proca, de Broglie and the development of relativistic
quantum theory in the 30’
Adrien Vila-Valls
18:00
67
News from the spallation neutron source SINQ: Diffraction
Jürg Schefer
18:15
68
Density functional calculations of polysynthetic
Brazil twinning in alpha-quartz
Hans Grimmer
18:30
Poster prize and closing remarks
18:35
END, Postersession and Apéro
20:15
Grillparty
16
Communications de la SSP No. 37
17:00
95
Density-functional-theory strategy to solve approximately a quantum many-body problem: main
ideas over the last 50 years and their reflection in
terminology
Tomasz Wesolowski
17:30
96
Political Decisions with deep Scientific Consequences
Araceli Sanchez Varela
18:00
97
A key to success for an instrument maker: Collaboration with a scientist. The case of Haag-Streit (established 1858) and Heinrich Wild (1833-1902).
Jean-François Loude
18:30
END, Postersession and Apéro
20:15
Grillparty
17:30
116 Search for spontaneous magnetism below the sur-
17:45
117 Ultrafast Enhancement of Ferromagnetism via Pho-
18:00
118 Coherent control of femtosecond magnetization
18:15
119 Ultrafast magnetism seen by time and spin resolved
face of (110)-oriented YBCO superconducting films
using LE-μSR
Hassan Saadaoui
toexcited Carriers in EuO
Masakazu Matsubara
dynamics by a strong THz pulse
Christoph Hauri
photoemission at FLASH
Andreas Fognini
18:30
Postersession and Apéro
20:15
Grillparty
Friday, 22.06.2012, HCI J 7
1 Magnetism at Interfaces
Time
Thursday, 21.06.2012, HCI J 7
Time
ID
Molecules and Cluster
Chair: Armin Kleibert, PSI Villigen
13:30
101 Magnetic exchange coupling at the metal-organic
14:00
102 Investigating the interplay of geometry and mag-
14:30
103 Novel magnetochemical effects induced by axial
molecule/substrate interface: Insights from firstprinciples calculations
Peter Oppeneer (i)
netism in spin shuttle molecules on surfaces
Thomas Greber (i)
ligands in on-surface planar molecular spin systems
Christian Wäckerlin
14:45
104 Magnetism of Fe nanocluster superlattices on
15:00
105 Towards spintronics with Erbium single-ion molec-
Al2O3/NiAl (111)
Luca Gragnaniello
ular magnets
Jan Dreiser
ID
Nanowires and Nanoparticles
Chair: Carlos Vaz, PSI Villigen
11:00
121 Static and dynamic properties of Single-Chain Mag-
11:15
122 Thermal fluctuations and domain walls in ultra-thin
11:30
123 Searching for magnetic structural excitations at the
11:45
124 Domain Walls in Structured Ferromagnetic Na-
12:00
125 Temperature-dependent magnetization of individu-
12:15
END, Postersession (continued), Lunchbuffet
nets with broad domain walls
Alessandro Vindigni
magnetic nanowires
Thomas Michaelis
nano-scale
Peter Derlet
nowires
Vahe Tshitoyan
al iron nanoparticles studied with X-ray Photoemission electron microscopy
Ana Balan
ID
Magnetism at Interfaces Poster
131
Use of a Landau-Heisenberg Hamiltonian in modelling the
FeRh System
Peter Derlet
132
Magnetization dynamics of GdFeCo nanostructures revealed with PEEM
Souliman el Moussaoui
133
tronic structure of the interfacial LaAlO3/SrTiO3
electron gas
Jean-Marc Triscone (i)
Coupled vortex pairs in magnetic multilayer elements
Christoph Quitmann
134
Ground state ordering of artificial spin ice
Alan Farhan
16:30
112 Interfacial magnetic couplings at LaSrMnO3 inter-
135
Domain pattern breakup in mesoscopic structures studied
with x-ray microscopy
Stephanie Stevenson
16:45
113 The Nature of Magnetic Ordering in Magnetically
136
Ultrafast laser induced spin reorientation in the Co/SmFeO3
heterostructure
Armin Kleibert
137
17:00
114 Strain-driven magnetization in epitaxial multiferroic
Studying the interfacial magnetism of LaNiO3/LaMnO3 superlattices with x-ray magnetic circular dichroism
Cinthia Piamonteze
138
Size-dependent magnetic properties of individual iron nanoparticles studied at room temperature
Ana Balan
139
Luminescence-based scanning x-ray transmission microscopy
Carlos Vaz
15:15
106 High anisotropies for bimetallic Co-core Fe-shell
islands on Au(11,12,12)
Sergio Vlaic
15:30
Coffee Break
Magnetic and Ultrafast Interfaces
Chair: Cinthia Piamonteze, PSI Villigen
16:00
17:15
111 Superconductivity, magneto-transport and elec-
faces
Carlos Vaz
Doped Topological Insulator Bi2-xFexSe3 - From Bulk
to Surface
Zaher Salman
composite heterostructures mapped with x-rays
and neutrons
Rajesh Chopedekar
115 Altering STO/vacuum interface electronic states
depositing polar LAO epitaxial film: Angle Resolved
Photoemission Spectroscopy study
Milan Radovic
17
SPG Mitteilungen Nr. 37
140
Enhancement of spin fluctuations of TbPc2 single molecule
magnets in thin films
Andrea Hofmann
15:00
217 Enhancing the Performance of Solid State Organic
141
Electric field control of magnetism in epitaxial Pd thin films
Jakoba Heidler
15:15
218 Wave Propagation in Elastic and Thermoelastic Ma-
142
Radiation-induced elemental magnetic changes in Fe-Cr alloys using XMCD technique
Andi Idhil
143
Impurity Band Responsible for Ferromagnetism in Magnetic Semiconductor (Ga,Mn)As
Masaki Kobayashi
144
Digging up Bulk Band Dispersion behind Passivation Layer
Masaki Kobayashi
145
Three-Dimensional Fermi Surface of Iron-Pnictide Superconductor BKFA
Masaki Kobayashi
Coffee Break
Applied Physics III
Chair: NN
Note:
The Atomic Physics and Quantum Optics Session
contains only poster presentations.
Friday, 22.06.2012, HCI J 6
ID
terials
Mario Leindl
15:30
2 Applied Physics
+
Atomic Physics and Quantum Optics
Time
Solar Cells by Self-assembled Monolayer Technique
Ali Kemal Havare
16:00
221 Highly efficient Cu(In,Ga)Se2 solar cells grown on
16:30
222 Dynamic nuclear polarization at moderate mag-
16:45
223 Dynamical study of electron pump based on self-
17:00
224 DAST/SiO2 multilayer structure for efficient genera-
17:15
225 Laser induced magnetization reversal in GdFeCo
17:30
226 Electrochemical deposition of photoconductive sili-
flexible polymer films
Adrian Chirilă (i)
netic fields and temperature using photo-excited
triplet states of aromatic molecules
Tim Rolf Eichhorn
assembled quantum dots
Giancarlo Cerulo
tion of 6 THz single-cycle pulses via cascaded optical rectification
Andrey Stepanov
nanostructures
Michele Buzzi
con based films using organic solvents
Agata Krywko-Cendrowska
17:45
Applied Physics I
Chair: Ivo Furno, CRPP-EPFL
END
ID
Applied Physics Poster
11:00
201 Vector Spherical Harmonics for active magnetic
241 Optical position feedback and closed loop control for elec-
11:15
202 Handling wide dynamic PMT signals with high pre-
242 Structural and piezoelectric investigation of BaTiO3 thin
11:30
203 A new internal field mapping device for the nEDM
243 Strain effects on the properties of III-V MOSFETs
11:45
204 High brilliance electron beam extraction from me-
12:00
trostatically driven MOEMS mirrors
Andreas Tortschanoff
field compensation
Grzegorz Wyszynski
films on Si
Marilyne Sousa
cision in ground-based gamma-ray detectors
Arno Gadola
Pirmin Weigele
experiment
Dieter Ries
244 Physical properties of ZnSe/SnO2/glass films: Annealing (Ar
atmosphere) temperature effects
Hulya Metin
tallic microstructured photocathode
Ardana Fernando
245 Structural and Electrical properties of Inkjet Printed CdS
Thin Films
Hulya Metin
Postersession (continued), Lunchbuffet
Applied Physics II
Chair: NN
13:30
13:45
14:00
14:15
246 Characterization of Inkjet Printed CdTe Thin Film
Hulya Metin
211 Cocaine Detection in Saliva with Attenuated Total
247 Electrical Properties and Crystallographic Properties of Ter-
Reflection (ATR) Spectroscopy
Kerstin Hans
nary Ho2O3 and Eu2O3 Doped Bi2O3 Polymorphs
Hulya Metin
212 Sensitive detection of cocaine in a liquid solvent
248 Electrical Properties And Crystallographic Characterisation
with a quantum cascade laser
Michele Gianella
of (Bi2O3)1-x-y(Ho2O3)x and (Tm2O3)y System
Hulya Metin
213 Mid-infrared fiber-coupled photoacoustic sensor
249 Surface morphology and Thermoluminescence of CBD
for the detection of glucose in biological samples
Jonas Kottmann
grown ZnSe Films
Selma Erat
214 Tracking of Murine Cardiac Stem Cells by Harmonic
250 Scattered light fluorescence microscopy in three dimensions
Nanoparticles
Thibaud Magouroux
14:30
215 Analysis of Human Tone-Burst-Evoked Otoacoustic
14:45
216 High power SESAM modelocked thin disk lasers:
Giulia Ghielmetti
251 Sensitivity of RADFETs with various gate oxide thicknesses
Goran Ristic
Emissions
Reinhart Frosch
access to sub-100 fs pulses and first CEO beat frequency detection
Cinia Schriber
18
Communications de la SSP No. 37
ID
Atomic Physics and Quantum Optics Poster
16:45
313 Muonium emission into vacuum from mesoporous
17:00
314 Qualification procedures of the CMS digital readout
17:15
315 Search for the Higgs boson in the diphoton decay
17:30
316 Measurements of the electron and muon inclusive
17:45
317 HammerCloud: distributed computing monitoring
18:00
318 Search for supersymmetry in hadronic final states
18:15
319 Angular correlation between B-hadrons produced
thin films at cryogenic temperatures
Kim Siang Khaw
281 Spectral properties of mid-infrared quantum cascade lasers
Lionel Tombez
282 Simple approximate relation between laser frequency noise
and linewidth: experimental validation
Nikola Bucalovic
283 External cavity tuning of broadband QCLs at 3.3 µm and 8 µm
chip for the Pixel Upgrade Phase I
Philipp Eller
channel at CMS
Marco Peruzzi
Sabine Riedi
284 Ground state Hanle effect based on atomic alignment:
theory and experiment.
Evelina Breschi
cross-sections in proton-proton collisions at s =
7 TeV with the ATLAS detector
Maria Clemencia Mora Herrera
285 Study of phase gradients in the Swiss continuous atomic
fountain frequency standard
Laurent Devenoges
for ATLAS and LHC experiments
Gianfranco Sciacca
286 Femtosecond gigahertz diode-pumped solid-state laser for
frequency comb generation
Alexander Klenner
with MT2 with the CMS detector
Hannsjörg Weber
287 Ultrafast optically pumped VECSELs and MIXSELs
Mario Mangold
288 Mid-IR Broadband Quantum Cascade Laser Frequency-
in association with a Z boson at the CMS experiment
Carlotta Favaro
Comb
Andreas Hugi
289 Single-cycle high-power THz pulses above 1 MV/cm
Carlo Vicario
18:30
Postersession and Apéro
20:15
Grillparty
Friday, 22.06.2012, HCI J 3
Time
3 Nuclear, Particle- and Astrophysics
Thursday, 21.06.2012, HCI J 3
Time
13:30
ID
TASK I: Neutrinos, Astroparticle Physics
Chair: Martin Pohl, Uni Genève
TASK III: LHC Physics II
Chair: T. Montaruli
11:00
321 Search for the Standard Model Higgs Boson decay-
11:15
322 New Optical receiver modules for the insertable B-
11:30
323 Improvements in the search for a Higgs boson de-
11:45
324 B-baryon studies at the CMS Experiment
301 Sterile neutrinos: dark matter, baryogenesis, magnetic fields and more...
Oleg Ruchayskiy
ID
ing to Bottom Quarks
Pierluigi Bortignon
Layer at the ATLAS project.
Basil Schneider
caying into bottom quarks
Philipp Eller
13:45
302 Dark Matter search with the XENON100 experiment
14:00
303 The Argon Dark Matter Experiment
14:15
304 Measurements of the low-energy response of liquid
14:30
305 Towards a large underground liquid argon observa-
13:30
331 Search for Supersymmetry in Events with a Z Bo-
14:45
306 On Flight Performances of the AMS-02 Detector
13:45
332 Searches for the 4th Generation top-like Quark
14:00
333 Top analysis from the bottom: Jet performance is-
14:15
334 Jet angular resolution
14:30
335 Measurement of the Zero-Crossing Point of the for-
14:45
336 Measurement of lifetime difference Ds in the decay
15:00
337 A data driven QCD-multijet background estimate
15:15
338 New searches for magnetic monopoles
Marc Schumann
Lukas Epprecht
12:00
tory for neutrino physics and proton decay
Alessandro Curioni
and Preliminary Results on the Proton and Helium
Energy Spectrum
Pierre Saoute
307 POLAR: a Gamma-Ray Burst Polarimeter in Space
15:15
308 The FACT telescope - overview and status
Silvio Orsi
Patrick Vogler
15:30
Coffee Break
TASK II: PSI Physics I and LHC Physics I
Chair: Klaus Kirch, ETH Zürich
16:00
311 New and final results of the MuCap experiment
16:30
312 Measurement of the Positive Pion Lifetime, tp+, with
Postersession (continued), Lunchbuffet
TASK IV: LHC Physics III
Chair: Antonio Ereditato, Uni Bern
xenon
Aaron Manalaysay
15:00
Mirena Ivova
Claude Petitjean
the FAST Detector at the Paul Scherrer Institute
Gaetano Barone
19
son, Jets and Missing Energy
Marco - Andrea Buchmann
Snezana Nektarijevi
sues in top quark measurements by the ATLAS experiment at the LHC.
Caterina Doglioni
Francesco Guescini
ward - backward Asymmetry of B0 " K*0 µ+ µMarco Tresch
Bs " (J/) " (µ+ µ-) K+ KBarbara Millan Mejias
for top physics with the ATLAS detector
Kilian Rosbach
Philippe Mermod
SPG Mitteilungen Nr. 37
Coffee Break
4 Theoretical Physics
TASK V: LHC Physics IV and PSI Physics II
Chair: Giuseppe Iacobucci, Uni Genève
Thursday, 21.06.2012, HCI J 4
15:30
16:00
341 Search for a neutron electric dipole moment at PSI
16:15
342 Systematic effects in the nEDM experiment at PSI
16:30
343 Improvements of the Hg cohabiting magnetometer
Johannes Zenner
for the nEDM experiment at PSI
Martin Fertl
16:45
344 Results of the active compensation of the magnetic
17:00
345 Simultaneous Heavy Flavor and Top (SHyFT) Cross
17:15
346 Radiation hard studies of diamond strip trackers
17:30
347 Search for the Rare Decays B0s " µ+ µ- and
17:45
18:00
18:15
18:30
ID
Time
Jochen Krempel
ID
13:30
401 Electron waiting time distributions in electrical con-
14:00
402 Gravitational wave detection from space
ductors
Markus Büttiker (i)
Philippe Jetzer (i)
14:30
field surrounding the nEDM apparatus at PSI
Beatrice Franke
15:30
Coffee Break
Theoretical Physics II
Chair: G. M. Graf, ETH Zürich
Section Measurement
Lukas Bäni
16:00
403 A new algorithm to compute one-loop scattering
16:15
404 Application of the Symbol Formalism to the Com-
16:30
405 Polycrystalline Shape Memory Alloys: Constitutive
16:45
406 One-dimensional fermionic systems beyond Lut-
17:00
407 Stability
17:15
408 Euclid and the quest for the Dark Energy
amplitudes
Fabio Cascioli
Felix Bachmair
B0 " µ+ µ- at LHCb
Christian Elsasser
putation of Scattering Amplitudes in Quantum Field
Theory
Erich Weihs
348 Search for (Higgs-like) bosons decaying into longlived exotic particles
Julien Rouvinet
Modelling by the BSM (Block-Spin-Method)
Eduard Oberaigner
349 Tagged time-dependent angular analysis of
B0s " J/  decays at LHCb
Frédéric Dupertuis
tinger liquid theory
Thomas Schmidt
350 b-baryon results at LHCb
Raphael Märki
END
Nuclear, Particle- and Astrophysics Poster
361
LOFT - the Large Observatory for X-ray Timing
Enrico Bozzo
362
The search for neutrinoless double beta decay with the
GERDA experiment
Giovanni Benato
Theoretical Physics I
Chair: G. M. Graf, ETH Zürich
of topological quantum computing
schemes to bit-flip and measurement errors
Ruben S. Andrist
Martin Kunz
17:30
18:30
Postersession and Apéro
20:15
Grillparty
363
Search for Physics Beyond the Standard Model in Events
with equally charged Leptons
Marc Dünser
364
Performance validation of the CMS digital readout chip with
x-rays for the Phase I Pixel Upgrade
Marco Rossini
365
Longitudinal spatial compression of a slow muon beam
Yu Bao
366
Optical cesium magnetometers for the PSI neutron electric
dipole moment experiment
Malgorzata Kasprzak
367
Search for Supersymmetry in multilepton final states
Tobias Kruker
368
Measurement of Pion and Kaon production cross sections
with NA61/SHINE for T2K
Silvestro di Luise
13:30
413 Cavity optomechanics in the single-photon strong-
369
Parametric r-process studies in supernova shocks
Marius Eichler
14:00
414 Controlling electronic interactions by light
370
Die Grundzüge der Weltpotentialtheorie
Peter Wolff
14:30
415 Hybridization of wave functions in one-dimensional
371
Das Lehrplakat zur Weltpotentialtheorie (WPT)
Peter Wolff
Friday, 22.06.2012, HCI J 4
Time
ID
Theoretical Physics III
Chair: G. M. Graf, ETH Zürich
11:00
411 The quantum marginal problem
11:30
412 What can we learn from the cosmological matter
12:00
Matthias Christandl (i)
distribution?
Ruth Durrer (i)
Postersession (continued), Lunchbuffet
Theoretical Physics IV
Chair: G. M. Graf, ETH Zürich
coupling regime
Andreas Nunnenkamp (i)
Philipp Werner (i)
Anderson localization
Dmitri Ivanov (i)
15:00
15:30
Coffee Break
Theoretical Physics V
Chair: G. M. Graf, ETH Zürich
16:00
20
416 Dynamics of the rotated Dicke model
Michael Tomka
Communications de la SSP No. 37
16:15
417 Bethe Ansatz and Ordinary Differential Equation
18:15
16:30
418 Eigenvector statistics in a perturbed weakly-
18:30
Postersession and Apéro
20:15
Grillparty
16:45
Correspondence for Degenerate Gaudin Models
Omar El Araby
confined random matrix ensemble
Matous Ringel
Friday, 22.06.2012, HPH G 1
Mario Leindl
END
Time
Thursday, 21.06.2012, HPH G 1
ID
MaNEP I
Chair: Dirk van der Marel, Uni Genève
501 Competition between charge order and supercon-
MaNEP III
Chair: Alberto Morpurgo, Uni Genève
521 Magnetoplasmons and Faraday rotation in graph-
11:30
522 Engineering Dirac points with ultracold fermions in
11:45
523 Transport through graphene on SrTiO3
12:00
ductivity in YBa2Cu3Oy
ID
11:00
5 NCCR MaNEP
13:30
faces: implications for understanding its origin
Mathilde L. Reinle-Schmitt
419 Symbolic Computation in Lagrangian Mechanics
17:00
Time
519 Tunable conductivity threshold at polar oxide inter-
ene
A. B. Kuzmenko (i)
a tunable optical lattice
Daniel Greif
Nuno Couto
Postersession (continued), Lunchbuffet
Marc-Henri Julien (i)
14:00
14:15
14:30
14:45
15:00
15:15
502
MaNEP IV
Chair: Frédéric Mila, EPFL
Scanning Tunneling Spectroscopy on YBa2Cu3O7−
revisited
Jens Bruér
13:30
531 Studying the physics of disordered bosons with dis-
14:00
532 Observation of a quantum critical point in the heavy
14:15
533 Antiferromagnetic spin-S chains with exactly di-
Compound T’-La2CuO4 of Electron-Doped Cuprates
Gwendolyne Pascua
14:30
534 Diagrammatic Monte Carlo for the Hubbard model
506 Field effect experiments on cuprates and related
14:45
535 Static and dynamic properties of a strong-leg spin
15:00
536 Zero field splitting in the two-dimensional quantum
15:15
537 Controlled flux penetration in platelet supercon-
503 Magnetic-field tuned anisotropy in superconducting RbxFe2−ySe2
Saskia Bosma
504 Universal scaling collapse of the dynamic relaxation rate in underdoped high Tc cuprates
Seyed Iman Mirzaei
505 Structural and Magnetic Properties of the Parent
materials
Guy Dubuis
507 Prospects for improving the superconducting properties of MgB2 and Nb3Sn wires
Carmine Senatore
15:30
Coffee Break
MaNEP II
Chair: Christoph Renner, Uni Genève
16:00
511 From surface to interface physics: High-energy
16:30
512 Theory of High-Temperature Multiferroicity in CuO
16:45
513 Radio-frequency spectroscopy of a weakly attractive Fermi gas
Christophe Berthod
17:15
515 Fermi Surface Dependence of the Charge Transport
17:30
roughness
Jill Guyonnet
and Thermoelectric Effect in Two-Dimensonal Metals
Jonathan M. Buhmann
516 Magnetotransport properties of LaAlO3/SrTiO3 interfaces
Alexandre Fête
17:45
517 Exchange Bias in LaNiO3-based heterostructures
18:00
518 Correlated transition metal oxides for thermo-
merized ground states
Frédéric Michaud
Jan Gukelberger
ladder
David Schmidiger
spin liquid PHCC
Maximilian Goldmann
ductors
Roland Willa
Coffee Break
MaNEP V
Chair: Andrey Zheludev, ETH Zürich
16:00
541 Spin-Orbital Separation in a Cuprate Spin Chain
16:30
542 Mapping of electron-hole excitations in a charge
16:45
543 Magnetism and orbital physics of the Mott insula-
17:00
544 Imprinting magnetic information in manganites with
Naemi Leo
514 Multiscaling analysis of ferroelectric domain wall
fermion antiferromagnet CeRhSi3
Nikola Egetenmeyer
15:30
photoemission spectroscopy of oxide heterostructures
Ralph Claessen (i)
17:00
ordered magnetic insulators
Tommaso Roscilde (i)
17:15
ID
Pavlo Zubko
and Studies of Fe-based Superconductors with
Resonant Inelastic X-ray Scattering
Thorsten Schmitt (i)
density wave system with Resonant Inelastic X-ray
Scattering
Claude Monney
tor LuVO3
Markos Skoulatos
X-rays
Marios Garganourakis
END
MaNEP Poster
5001 Soft x-ray photoemission measurements on LaAlO3/SrTiO3
and (LaAlO3)x(SrTiO3)1−x/SrTiO3 heterostructures
Claudia Cancellieri
electrics
Sascha Populoh
21
SPG Mitteilungen Nr. 37
5002 Bond disorder in Cu(quinoxaline)X2, X = Cl, Br
5026 Humidity Sensing Properties of Different Bismuth Phosphate Types
Min Sheng
Wolfram E. A. Lorenz
5003
Asymmetric Josephson effect at the interface of non-centrosymmetric superconductors
Ludwig Klam
5027 Optical Measurements of Neodymium and Samarium Nickelates
Julien Ruppen
5004 Electron-hole instability in TiSe2
5028 Structural study of LaNiO3 heterostructures at the metal-
Gael Monney
insulator transition
Steven J. Leake
5005 µSR investigation of magnetism and magnetoelectric coupling in Cu2OSeO3
Aleander Maisuradze
5029 Effect of phase separation and vacancy order on the superconducting and magnetic properties of RbxFe2−ySe2
Steven Weyeneth
5006 Multiscaling analysis of intrinsic domain walls in epitaxial
BiFeO3 thin films
Benedikt Ziegler
5007
5030 The effect of nitrogen incorporation on the thermoelectric
properties of EuTiO3 and EuTi0.98Nb0.02O3
Leyre Sagarna
Phase diagram of epitaxial BiFeO3-LaFeO3 Superlattices
Gijsbert Rispens
5031 Semiclassical theory of the 1/2 magnetization plateau of
5008 Multiplet calculations and X-ray spectra simulations in low
the J1-J2 model on the square lattice
Tommaso Coletta
symmetry compounds.
Anne-Christine Uldry
5032 Infrared Spectroscopy on Gated Tri-layer Graphene
5009 Field driven ordering in a frustrated spin ladder with bond
Nicolas Ubrig
randomness
Erik Wulf
5033 Hysteresis in the temperature dependent electronic structure of NdNiO3: A photoemission study
Zuzana Vydrová
5010 Thermoelectric effect in one-dimensional metallic systems
- a model study on the impact of disorder and phonons
Daniel Müller
5011
5034 Mixed crystals from the quantum magnets Ba3Cr2O8 and
Sr3Cr2O8
Henrik Grundmann
Graphene on Ruthenium: Four hills
Irakli Kalichava
5035 Influence of different synthesis methods on thermoelectric
5012 Nanoscale PFM imaging of intrinsic domains in PbTiO3 ul-
properties of Ti0.33Zr0.33Hf0.33NiSn half-Heusler compound
with emphasis on thermal conductivity measurements
Krzysztof Galazka
trathin films.
Céline Lichtensteiger
5013 Pressure dependence of optical exitations in tetragonal
5036 Self-consistent structure of a domain wall in Sr2RuO4
Sr2VO4
Michael Tran
Adrien Bouhon
5037 Realization of a thermal LC-circuit
5014 Doping and temperature dependence of STS spectra in
Olaf Bossen
Bi2Sr2Ca1Cu2O8+
Thomas B. Amundsen
5038 Competition between columnar and plaquette order in the
fully frustrated transverse field Ising model on the square
lattice.
Sandro Wenzel
5015 Scanning tunnelling microscopy/spectroscopy study of
La2/3Ca1/3MnO3 thin films
Zoran Ristic
5039 Hybridization gap and anisotropic far-infrared optical con-
5016 First direct observation of the Van Hove Singularity in the
ductivity of URu2Si2
Julien Levallois
tunnelling spectra of cuprates
Alexandre Piriou
5040 The influence of defects in the quasi-2D CDW compound
5017 Effect of bond disorder on weakly-coupled spin-1/2 antifer-
1T-TiSe2
Clément Didiot
romagnetic Heisenberg chains
Matthias Thede
5041 A Thermoelectric Study on the Electron Gas at the LaAlO3/
5018 CVD graphene: effects of the environment and annealing
SrTiO3 Interface
Danfeng Li
on its doping level and the charge carriers mobility
Christophe Caillier
5042 Disorder in a quasi-two-dimensional quantum spin liquid
5019 Nearest-neighbor spin correlations and doublon produc-
Dan Hüvonen
tion rate by lattice modulation for spin-1/2 fermionic atoms
Akiyuki Tokuno
5020
5043 Resonant inelastic x-ray scattering on a quasi-one-dimen-
sional multiferroic cuprate: probing the local magnetic correlations
Claude Monney
New experimental setup for thermal conductivity measurements: stability against quench in industrial Nb3Sn wires
fabricated by various techniques
Marco Bonura
5044 Critical current of Nb3Sn wires under quasi-hydrostatic radial pressure
Giorgio Mondonico
5021 Temperature and time scaling of the peak-effect vortex
configuration in FeTe0.7Se0.3
Marco Bonura
5022
5045 Phase diagram of the EuFe2As2 system with respect to
chemical and hydrostatic pressure
Zurab Guguchia
Physical properties of TiSe2 crystals grown by vapour
transport technique.
Alberto Ubaldini
5046 On Electronic Properties and Superconductivity of Strained
High Tc Films
Nathaniel Wooding
5023 Bulk insulating states in the Bi2(Se1−xTex)3 solid solution.
Alberto Ubaldini
5047 Effects of bond disorder in the quantum spin ladder
5024 Optical properties of Bi2Te2Se
(C5H12N)2CuBr4(1-x)Cl4x
Simon Ward
Ana Akrap
5025 Interactions between carbon nanotubes and epitaxial
Pb(Zr0.2Ti0.8)O3 thin films
Cédric Blaser
22
Communications de la SSP No. 37
6 NCCR Nano
5048 Nanoscale studies of electrical conduction in ferroelectric
domain walls with insulator coated carbon nanotube tips
Yuliya Lisunova
I. Nanomechanics
5049 Influence of the Internal Polarizability on the Charge Trans-
Thursday, 21.06.2012, HCI G 3
port Properties in N-Type Organic Single Crystal Field-Effect Transistors
Nikolas Minder
Time
ID
5050 Control of the magnetic volume fraction in Co-doped TiO2
films via oxygen vacancies
Hassan Saadaoui
5051 Structural and electrical properties of BaTiO3 thin-film capacitors
Stephanie Fernandez-Pena
13:30
601 Coherent coupling of light and mechanical motion
14:00
602 Stable "ring-like" Ag clusters on Si(111)-(7×7): volt-
14:15
603 Detection of cantilever thermal motion and feed-
14:30
604 Entering the nonlinear regime with mechanical res-
15:00
605 The Lateral Resolution of the near-tip scanning
15:15
606 Prospects and challenges for atomic force micros-
Ewold Verhagen (i)
age dependency study of the scanning tunneling
microscopy apparent topography
Nicolas Mariotti
5052 One-dimensional nanolines and single atom chains on
Si(001)
François Bianco
back cooling using a quantum point contact
Michele Montinaro
5053 Frustration and disorder in a 1D spin ladder at high magnetic fields
Toni Shiroka
onators made from nanotubes and graphene
Alexander Eichler (i)
5054 Tuning superconductivity and magnetism in FeySe1−xTex
Markus Bendele
electron microscopy.
Danilo Pescia
5055 Superconductivity Driven Imbalance of the Magnetic Domain Population in CeCoIn5
Simon Gerber
copy in molecular structure recognition
Bruno Schuler
5056 Ultrafast X-Ray Nanowire Single-Photon Detectors and
Their Energy-Dependent Response
Kevin Inderbitzin
Nanomechanics
Chair: Martino Poggio, Uni Basel
15:30
5057 Magnetic phase transitions in PbBxB’1−xO3 (B = Fe, and
B’ = Nb, Ta)
Shravani Chillal
Coffee Break
16:00
607 Non-contact friction measurements by means of
16:30
608 NanoXAS - Combining Scanning Probe and X-Ray
Atomic Force Microscopy (AFM) operated in pendulum geometry
Marcin Kisiel (i)
5058 Differences in Chiral Expression: Racemic and Enantiopure
Heptahelicenes on Various Metal Surfaces
Johannes Seibel
Microscopy for Nanoanalytics
Nicolas Pilet
5059 The Luttinger liquid theory of molybdenum purple bronze
Piotr Chudzinski
5060 Temperature-Dependence of Detection Efficiency in NbN
and TaN SNSPD
Andreas Engel
16:45
END
18:30
Postersession and Apéro
20:15
Grillparty
5061 Electronic Properties of Single-Crystal Organic Charge-
II. Nanophotonics & Varia
Transfer Interfaces probed using Schottky-Gated Heterostructures
Ignacio Gutierrez Lezama
Thursday, 21.06.2012, HCI G 7
5062 Crossover from Coulomb blockade to quantum-Hall effect
in suspended graphene nanoribbon
DongKeun Ki
Time
5063 Doping dependence of the pseudogap phase in La-based
cuprates
Christian Matt
5064 Soft-X-Ray ARPES: From Three-Dimensional Materials to
Heterostructures
Vladimir N. Strocov
5065 Conduction at domain walls in insulating Pb(Zr0.2Ti0.8)O3
Iaroslav Gaponenko
621 Towards time-resolved 3D imaging and probing
14:00
622 Study of the Optical Transport within Plasmonic
14:15
623 Nanoscale Chemical Analysis by Tip-Enhanced Ra-
14:45
624 Gold Photoluminescence in Nanoscale Antennas
15:00
625 3-Dimensional Computational Nano-Optics - With a
5067 Local study of the electronic and structural properties of
colloidal semiconductor nanocrystals
Maria Longobardi
5068 Pressure dependence of the penetration depth in CeCoIn5
studied by muon spin rotation
Ludovic Howald
Nanophotonics I
Chair: Olivier Martin, EPFL
13:30
5066 Fluctuations of one-dimensional interface in the directed
polymer formulation: role of a finite interface width
Elisabeth Agoritsas
ID
with Photonic Force Microspectroscopy
Sylvia Jeney (i)
Nano- and Sub Nano-metric Junctions
Banafsheh Abasahl
man Spectroscopy: Recent Developments and Applications
Thomas Schmid (i)
Toni Fröhlich
Focus on Fabricated Structures
Benedikt Oswald (i)
15:30
Coffee Break
Various Nanotopics
Chair: NN
5069 Hexagonal InMnO3 - An Outsider Among The Family Of Multiferroic Hexagonal Manganites
Martin Lilienblum
16:00
23
631 Imaging the charge distribution within a single molecule
Fabian Mohn (i)
SPG Mitteilungen Nr. 37
16:30
632 Chemical sensing with silicon nanowire field-effect
15:00
16:45
633 Combining SFM & ToF-SIMS: a new route to access
15:15
END
15:30
Coffee Break
17:00
transistors
Ralph Stoop
chemical information at the nanoscale
Laetitia Bernard
634 Progress in electron beam generation for Near
Field-Emission Scanning Electron Microscopy
Danilo Andrea Zanin
17:15
635 New Developments in Near Field-Emission Scan-
17:30
636 Electrostatic characterization of Near Field-Emis-
17:45
637 Resonances arising from hydrodynamic memory -
18:00
ning Electron Microscopy
Lorenzo G. De Pietro
ID
Nano Poster
671
Optomechanical Coupling of Ultracold Atoms and a Membrane Oscillator
Maria Korppi
isotropic surface of an organic layer compound crystal
Gregor Fessler
673 Near Field-Emission Scanning Electron Microscopy
Peter Thalmann
The Color of Brownian motion
Matthias Grimm
674 Electron Beam Properties of Large Double Gate Field Emitter Arrays with an Optimized Collimation Gate Electrode Geometry
Patrick Helfenstein
638 Graphane formation and patterning by pure hydrogen low temperature plasma exposure
Baran Eren
675 Fabrication and characterization of tunable plasmonic na-
18:15
nostructures for biosensing
Olivier Scholder
Postersession and Apéro
676 Study of biomolecular interactions using photonic crystal
surface waves (PC SW) optical sensor.
Tatyana Karakouz
Friday, 22.06.2012, HCI G 7
Time
13:30
ID
Nanophotonics II
Chair: Olivier Martin, EPFL
641 Plasmonic Promises: Single Molecule Sensing,
Electrochemistry, Nanowire Electronics, Strain Visualization, and Interferometry
Janos Vörös (i)
14:00
642 Periodic nanogap arrays for surface enhanced
14:15
643 Targeting cells with gold nanoparticles
14:45
644 Electron emission from optically excited metallic
15:00
645 Organic LEDs
7 NCCR MUST
Friday, 22.06.2012, HPH G 2
spectroscopy: modeling and performance
Thomas Siegfried
Time
Sara Peters (i)
nanotips
Anna Mustonen
END, Coffee Break
11:30
702 Electron ionization times measured with the atto-
11:45
703 Attosecond Time-Gated Absorption and Emission
Friday, 22.06.2012, HCI J 7
13:30
ID
MUST I
Chair: Lukas Gallmann, ETH Zürich
701 Probing electronic valence shell dynamics in mol-
12:00
III. Nanobiophysics
ID
11:00
Beat Ruhstaller (i)
15:30
Time
for Medical Breath Testing
Hans Peter Lang
672 Friction anisotropy investigations: Measurements on the an-
sion Scanning Electron Microscopy
Hugo Cabrera
18:30
666 Microfabricated Membrane Surface Stress Sensors
ecules
Hans Jakob Wörner (i)
clock
Robert Boge
Jens Herrmann
Postersession (continued), Lunchbuffet
Public Tutorial see p. 15
MUST II
Chair: Thomas Feurer, Uni Bern
Nanopbiophysics
Chair: Georg Fantner, EPFL
13:30
711 Optimal Dynamic Discrimination of Free Amino Ac-
13:45
712 Dynamic probe concept for studying aggregation
661 Nanophotonics and Nanoelectronics Tools for
Single Molecule Biophysics
Aleksandra Radenovic (i)
ids and Small Peptides
Jean-Pierre Wolf
of organic dye molecules at liquid/liquid interfaces
by femtosecond second harmonic generation technique
Marina Fedoseeva
14:00
662 Investigating Skin Cancer with Nanomechanical
14:15
663 Optimization of DNA hybridization efficiency by pH-
14:00
713 Breaking Down the Problem to Understand the
14:30
664 Study of DNA relaxation on mica using AFM with
14:15
714 Investigation of low frequency vibrations using dis-
14:45
665 Direct Visualization of Lipid Membrane Dynamics
14:30
715 Multidimensional IR spectroscopy of water
Biosensors
François Huber
driven nanomechanical bending
Jiayun Zhang
further automatic tracing
Andrey Mikhaylov
Using High-Speed Atomic Force Microscopy (HSAFM)
Jonathan D. Adams
24
Photophysics of Conjugated Polymers
Natalie Banerji
persed femtosecond – DFWM
Gregor Knopp
Peter Hamm (i)
Communications de la SSP No. 37
15:00
15:15
716 Measuring nonadiabaticity of molecular quantum
748 Towards femtosecond dynamics in multiferroics
dynamics with quantum fidelity and with its efficient semiclassical approximation
Tomáš Zimmerman
Teresa Kubacka
749 Photon echo measurements using a frequency doubled cavity dumped femtosecond oscillator
Vesna Markovic
717 Perturbative Treatment of the Up-Conversion Detection of Pulse-shaped Entangled Photons and
Applications
Christof Bernhard
15:30
750 A Combined NIR Transient-Absorption Optical Pump-THz
Probe Spectroscopy Study on Charge Carrier Generation
Dynamics in Solid State Dye Sensitized Solar Cells
Jan Brauer
Coffee Break
751 Investigation of chemical surface treatment on the charge
MUST III
Chair: Jürg Osterwalder, Uni Zürich
16:00
16:15
16:30
carrier dynamics in solid-state Dye-Sensitized Solar Cells
Arianna Marchioro
721 High-harmonic generation from oriented OCS mol-
752 Photoinduced Processes of Small Molecule Organic Photo-
ecules
Peter Kraus
voltaics
Jelissa De Jongh
722 A double-sided time-resolved VMI setup with high
753 Photoelectron Diffraction on SnPc/Ag(111)
temporal resolution
Yuzhu Liu
Michael Greif
754 Effects of the finite length of the pump laser pulse in nona-
723 Femtosecond dynamics of atomic structure in sol-
diabatic quantum dynamics simulations of ultrafast timeresolved spectroscopy
Aurélien Patoz
ids
Steve L. Johnson (i)
Chair: Paul Beaud, PSI Villigen
17:00
724 Femtosecond Transient Diffuse Reflectance for
17:15
725 p-Conjugated Donor-Acceptor Systems as Metal-
17:30
17:45
18:00
755 Accelerating calculations of ultrafast time-resolved electronic spectra with various high order split-operator algorithms
Marius Wehrle
Dye-Sensitized Solar Cells
Elham Ghadir
756 High-harmonic spectroscopy of isoelectronic molecules:
Free Sensitizers for Dye-Sensitized Solar Cell Applications
Mateusz Wielopolski
electronic structure and multielectron effects
Alisa Rupenyan-Vasileva
757 Actively Stabilized Attosecond Interferometer
726 Probing interfacial electron transfer dynamics in
Martin Huppert
the attosecond time domain
Luca Castiglioni
758 Ultrafast time-resolved photoelectron spectroscopy of solvated systems
Inga Jordan
727 Atomic motion of a coherent phonon observed in a
charge and orbitally ordered manganite
Andrin Caviezel
759 Versatile velocity-map-imaging spectrometer for strongfield and attosecond experiments
Samuel Walt
728 Electron dynamics in a quasi-1-dimensional topological metal: Bi(114)
Matthias Hengsberger
760 Versatile Non Collinear Four-Wave Mixing Set-Up Fully
18:15
729 Laser induced coherent structural dynamics of the
18:30
730 Non-retarded pairing interaction in a high-Tc cu-
Based on Femtosecond Pulse Shaping for Coherent Electronic Spectroscopy
Franziska Frei
Heusler alloy Ni2MnGa
Simon O Mariager
761 Field Enhancement in THz nano-structures
Fabian Brunner
prate from coherent charge fluctuation spectroscopy
Fabrizio Carbone (i)
19:00
762 Femtosecond surface second harmonic generation microscopy to probe adsorbed layers at interfaces
Delphine Schaming
END
ID
763 Time resolved surface second harmonic generation and
electron transfer reactions at liquid-liquid interfaces
Astrid Olaya
MUST Poster
741 Direct High Harmonics Pulse Shaping in the XUV
Jean-Pierre Wolf
742 High-Power Mid-infrared Femtosecond Laser Source Based
On Parametric Transfer
C. Heese
8 NCCR QSIT
743 Stereochemistry of C4 dicarboxylic acids on Cu(110)
Friday, 22.06.2012, HCI G 3
Chrysanthi Karageorgaki
744 Beating the efficiency of both quantum and classical simulations with semiclassics
Cesare Mollica
Time
745 Confocal fs-CARS measurement of nano-particles in epidirection
Gregor Knopp
746 Probing the longitudinal momentum spread of the electron
wave packet at the exit point
Alexandra Landsman
747 Accelerating the calculation of time-resolved electronic
spectra with the cellular dephasing representation
Miroslav Šulc
25
ID
QSIT I
Chair: Richard Waburton, Uni Basel
11:00
801 Torque Magnetometry of Individual Ni Nanotubes
11:15
802 Characterization of nano-scale electrical contacts
11:30
803 Scanning gate experiments on graphene nanorib-
Dennis P. Weber
using dynamical Coulomb blockade
Konrad H. Müller
bons
Nikola Pascher
SPG Mitteilungen Nr. 37
11:45
804 All Electrical Control and Slowing of Microwaves
848 Cold collisions in an ion - atom hybrid trap
using Circuit Nano-electromechanics
Xiaoqing Zhou
12:00
Felix Hall
849 Design and development of a surface electrode ion trap for
Postersession (continued), Lunchbuffet
sympathetically cooled molecular ions
Arezoo Mokhberi
QSIT II
Chair: Klaus Ensslin, ETH Zürich
13:30
811 Graphene Quantum Dots
14:00
812 Rectification of thermal fluctuations in a chaotic
850 Density Matrix Renormalization Group for Optical Lattices
Michele Dolfi
851 In search of operational quantities for characterizing large
Johannes Güttinger (i)
quantum systems
Normand Beaudry
cavity heat engine
Björn Sothmann
852 On the Optimality of Work Extraction in Small Thermody-
14:15
813 Fiber-cavity spectroscopy of quantum wells and
14:30
814 Supplying cluster states for one-way quantum
14:45
815 Multilevel transport in a three-terminal graphene
namical Systems
Philippe Faist
charge-controlled quantum dots
Javier Miguel-Sanchez
computing
Daniel Becker
9 Earth, Atmosphere and Environmental Physics
quantum dot
Pauline Simonet
Thursday, 21.06.2012, HCI D 8
15:00
816 Quantum Hall effect in Graphene with supercon-
15:15
817 Quantum Metrology with a Scanning Probe Atom
ducting electrodes
Peter Rickhaus
Interferometer
Caspar Ockeloen
15:30
Time
ID
13:45
901
Ionising radiation in the Environment
Christophe Murith (i)
14:15
902
Influence of Galactic Cosmic Rays on the atmospheric composition and temperature
Marco Calisto
14:30
903
Laser-induced aerosol generation in air
Massimo Petrarca
14:45
904
Wind gusts parametrization methods for winter
storms in Switzerland with the Canadian Regional
Climate Model
Charles-Antoine Kuszli
15:00
905
A Study of Interface Effects Between Porous and
Double Porous Media
Eduard Oberaigner
15:15
906
Fiber bundle models for granular shearing and
acoustic emissions during landslide initiation
Denis Cohen
Coffee Break
QSIT III
Chair: Matthias Christandl, ETH Zürich
16:00
821 Dark state spectroscopy of a single hole spin
16:30
822 Exploring cavity-mediated long-range interactions
16:45
823 Density functional theory for static and dynamic
17:00
824 Quantum state tomography of 1000 bosons:
17:15
825 Ultrastrong Coupling of the Cyclotron Transition of
Julien Houel (i)
in a dilute quantum gas
Renate Landig
properties of atomic quantum gases
Lei Wang
reduced density matrices
Michael Walter
15:30
Coffee Break
II: Resources (Geology, Materials, Biofuels,
Energy & LCA)
Chair: Antoine Pochelon, EPFL-CRPP
a 2D Electron Gas to a THz Metamaterial
Curdin Maissen
17:30
END
ID
I: Atmosphere and Geohysics
Chair: Stéphane Goyette, Uni Genève
16:00
911
Deep structure of the Swiss Plateau from seismicwave sounding: a new 3D seismic model of the
Swiss Molasse Basin
François Marillier (i)
16:30
912
Scarce metals - Applications, supply risks and
need for action
Patrick A. Wäger (i)
17:00
913
Roundtable on Sustainable Biofuels: Ensuring Biofuels Deliver on their Promises
Sebastien Haye (i)
17:30
914
Energy resources, energy choices and life cycle
assessment
Andrew Simons (i)
QSIT Poster
841 Electronic transport in ultra-clean carbon nanotube quantum dots
Stefan Nau
842 Quantum dots in the quantum Hall regime
Stephan Baer
843 Progress toward nanoscale magnetic resonance with a
"magnet-on-cantilever" force microscope
Phani Peddibhotla
844 Tunnel barriers for spin injection into graphene
Matthias Bräuninger
845 A hybrid on-chip opto-nanomechanical transducer for ultrasensitive force measurements
Emanuel Gavartin
846 Probing charge noise in a semiconductor with laser spectroscopy on a single quantum dot
Andreas Kuhlmann
847 Geometric phase gates for trapped molecular ions
Matthias Germann
26
18:00
END
18:30
Postersession and Apéro
20:15
Grillparty
Communications de la SSP No. 37
Aussteller - Exposants
Agilent Technologies, CH-4052 Basel
www.agilent.com
Meili-Kryotech, CH-7433 Donat
www.kryotech.ch
attocube systems AG, DE-80539 München
www.attocube.com
NanoScan AG, CH-8600 Dübendorf
www.nanoscan.ch
Bruker AXS GmbH, DE-76187 Karlsruhe
www.bruker.com
Oxford Cryosystems Ltd, UK-Long Hanborough, OX29 8LN
www.oxcryo.com
DECTRIS Ltd, CH-5400 Baden
www.dectris.com
Schäfer-Tec AG, CH-3422 Kirchberg BE
www.schaefer-tec.com
Dyneos AG, CH-8307 Effretikon
www.dyneos.ch
SENTECH GmbH, DE-82152 Krailing
www.sentech-sales.de
EPL-IOP, UK-Bristol
www.iop.org
Stoe & Cie GmbH, DE-64295 Darmstadt
www.stoe.com
GMP SA, CH-1020 Renens
www.gmp.ch
Swiss Vaccum Technologies S.A., CH-2022 Bevaix
www.swissvacuum.com
Hiden Analytical Ltd., UK-Warrington, WA5 7UN
www.hidenanalytical.com
TECO René Koch, CH-1807 Blonay
www.teco-rene-koch.com
HORIBA Jobin Yvon GmbH, DE-64625 Bensheim
www.horiba.com/de/scientific
VG Scienta, UK-Hastings, East Sussex, TN38 9NN
www.vgscienta.com
Hositrad Deutschland Vacuum Technology,
DE-93047 Regensburg
www.hositrad.com
VACOM GmbH, DE-07749 Jena
www.vacom.de
Zurich Instruments, CH-8005 Zürich
www.zhinst.com
MaTecK GmbH, DE-52428 Jülich
www.mateck.de
Kurzmitteilungen
Patenschaft für Maturaarbeiten
Ernennung von SATW-Mitgliedern
Die Akademie der Naturwissenschaften Schweiz (SCNAT)
sucht ExpertInnen, die an 4 Halbtagen im Jahr Maturaarbeiten von Mittelschülern in allen naturwissenschaftlichen
Fächern (Biologie, Chemie, Geowissenschaften, Informatik,
Mathematik, Physik) betreuen wollen.
Die Schweizerische Akademie der Technischen Wissenschaften (SATW) hat an ihrer Mitgliederversammlung am
26. April 2012 folgende SPG Mitglieder zu ordentlichen
Einzelmitgliedern ernannt:
Dr. Rolf Allenspach, Dr. Pierangelo Gröning und Dr. Thomas
von Waldkirch.
Der SPG-Vorstand freut sich über die ehrenvolle Ernennung
und beglückwünscht die Kollegen aufs herzlichste.
Hauptziel der Initiative «Patenschaft für Maturaarbeiten» ist
es, die Begeisterung für naturwissenschaftliche Berufe zu
wecken und den GymnasiastInnen einen Blick in die Berufswelt zu ermöglichen. Dieses Angebot bietet den SchülerInnen die einmalige Möglichkeit, mit Wissenschaftern von
Hochschulen oder aus der Industrie in Kontakt zu treten,
spezifische Messgeräte zu benutzen und Forschungsluft zu
schnuppern. Die Jugendlichen investieren viel in diese Arbeiten (ungefähr 1 Halbtag/Woche während eines Jahres)
und lernen gleichzeitig die verschiedenen Karrieremöglichkeiten in den Naturwissenschaften kennen.
Joint EPS-SIF International School on Energy
New Strategies for Energy Generation, Conversion and
Storage
30 July - 4 August 2012, Villa Monastero, Varenna (Lake
Como)
Directors: L. Cifarelli (Università di Bologna), F. Wagner
(Max-Planck-Institut für Plasmaphysik, Greifswald), D. S.
Wiersma (LENS, Firenze)
Contact person: M. Burresi - [email protected]
More information:
http://en.sif.it/activities/energy_school/2012
Im 2011 hat die SCNAT beschlossen, angelehnt an die
Patenschaften ein neues Angebot im Bereich Nachwuchsförderung zu entwickeln. Wir haben festgestellt, dass die
Schulen regelmässig ReferentInnen suchen, die aus ihren
Forschungsgebieten berichten möchten. Es soll deshalb
eine Liste mit ExpertInnen geführt werden, die bereit sind,
ihre Arbeit SchülerInnen der Sekundarstufe II (15 – 18 Jahre
alt) vorzustellen.
Weitere Informationen: www.maturitywork.scnat.ch
27
SPG Mitteilungen Nr. 37
Progress in Physics (28)
In der Reihe "Progress in Physics" berichten Physikerinnen und Physiker über ihre Aktivitäten an schweizerischen Hochschulen und Industrien. Jedes SPG - Vorstandsmitglied kommt zyklisch an die Reihe, einen Artikel zu acquirieren. Mit
dieser Vorgangsweise wird zwar für eine gewisse thematische Breite gesorgt, aber eine Sichtung der bisherigen Beiträge
zeigt, dass aus der Industrie bislang wenig kam. Das heisst aber nicht, dass die Industrie an Forschungsergebnissen nicht
interessiert sei, aber sie müssen eine erste Umsetzbarkeit erkennen lassen. Wie man Innovation und Realisierung näher
zusammenbringt, ist Anliegen des SATW-Forums, über dessen jüngste Veranstaltung im November 2011 im folgenden
berichtet wird.
SATW Forum "Advanced Optoceramics"
Bernhard Braunecker und Rolf Hügli (SATW)
In der 2010 gestarteten Reihe des "SATW Forums" sollen
neue Erkenntnisse über ein aktuelles Technologiethema im
kleinen Kreis von Experten besprochen werden. Die jeweils
behandelte Technologie sollte im Ansatz neuartig, jedoch
physikalisch im Labor verifiziert sein, und sie sollte noch
einer industriellen Umsetzung harren, aber bereits ein attraktives Marktpotential für Produkte erkennen lassen.
Von - zumindest in dieser Phase - minderer Bedeutung ist,
wenn der Weg von der Laborverifizierung zum industriellen
Produkt bislang noch als zu risikoreich eingeschätzt wird,
da sich gerade dies durchaus als Wettbewerbsvorteil für
die hiesigen Hochschulen und Industrien erweisen könnte.
Die Diskussion im Forumskreis soll primär zeigen, ob auf
Seiten von Hochschule und Industrie nicht nur fachliche
Kompetenz, sondern auch ein gemeinsames Interesse an
einer Weiterentwicklung der Technologie zur Produktreife
gegeben ist, und wie die Chancen einer solchen Realisierung beurteilt werden? Letzten Endes soll ausgelotet werden, ob durch eine gemeinsame Aktion Grundlagen gelegt
werden können, um neue, hochwertige Arbeitsplätze in der
Schweiz mittel- bis langfristig zu schaffen.
Bei der Auswahl der Themen sollte deshalb darauf geachtet
werden, dass die Technologie trotz ihrer Neuartigkeit auf einer gewissen Tradition in der Schweiz wie Miniaturisierung,
Höchstpräzision, Umweltverträglichkeit aufbauen kann, um
politische Akzeptanz und Verständnis in der Öffentlichkeit
zu finden. Zudem erscheint sinnvoll, dass die Themen im
evolutionären Sinne eine Weiterführung früherer Aktivitäten
wie zum Beispiel eine Umsetzung der Nanotechnik sind.
Über sie wurden in der Schweiz in den vorangegangenen
Jahren sowohl auf akademischer wie industrieller Seite genügend neue Erkenntnisse prinzipieller Natur gewonnen,
um die bereits angesprochenen Risiken bei einer Weiterführung zu minimieren.
Die Forumsreihe fokussiert sich somit auf drei Kernanliegen
der SATW, nämlich der Früherkennung von Technologien,
der Netzwerkbildung und der Gewinnung optimaler Akzeptanz der Technologie durch die Öffentlichkeit, was im Wesentlichen durch eine frühzeitige Auseinandersetzung mit
ethischen Grundsätzen geschieht.
Optokeramiken
Als Thema des zweiten Forums wurde Advanced Optoceramics gewählt. Optokeramiken gehören zur Klasse der
oxidisch-mineralischen Werkstoffe, die ein breites Applikationsspektrum von Hochspannungsisolatoren bis zu Medizinalanwendungen abdecken. 1987 erhielten J. G. Bednorz
und K. A. Müller vom IBM Forschungszentrum in Rüschlikon
den Nobelpreis für ihre Pionierarbeiten an auf Oxidkeramik
basierenden Hochtemperatur-Supraleitern. In der Schweiz
werden Keramiken schwerpunktsmässig bei der EMPA, an
beiden ETHs, aber auch in der Industrie behandelt.
Generell zeichnen sich diese Werkstoffe dadurch aus, dass
sich durch gezielte Dotierung der Keramikmatrix mit Fremdpartikeln die mechanischen, elektrischen, thermischen und
optischen Eigenschaften verändern lassen. Das geschieht
über einen mehrstufigen und die Nanotechnik einbeziehenden Herstellprozess. Man zermahlt die Werkstoffe zu
Im Abbe-Diagramm liegen links unten die Gläser mit
niederer Brechzahl und schwacher Dispersion, rechts
oben die hochbrechenden, aber leider auch mit starker
Dispersion versehenen Gläser. Für den Optikdesign
ideal wären Gläser in der Gegend des Bildes von Ernst
Abbe. Nur beginnen die Gläser nahe einer magischen Linie auszukristallisieren, was sie technisch unbrauchbar
macht. Anstatt nun gegen die Kristallisierung vergeblich
anzukämpfen, macht es mehr Sinn, gleich auf Keramiken
zu setzen und diese in ihren optischen Eigenschaften
gleichwertig zu Gläsern zu machen. Die Blasen im Diagramm zeigen Bereiche von Optokeramiken, wo in guter
optischer Qualität bereits Prototypen vorliegen, und die
sich in ihrer Transmission, in den Teildispersionen, etc.
voneinander unterscheiden.
28
Communications de la SSP No. 37
Nanopulver, dotiert und kommt über geeignete Press- und
Sinterprozesse zurück zu makroskopisch handhabbaren
Proben. Da die Dopingrate beim heterogenen NanopulverKonvolut deutlich grösser sein kann als beim Einkristall,
sind höhere Effizienzen bei bestimmten Materialeigenschaften zu erwarten.
Da jedoch das Thema "Keramik" in seiner vollen Breite eine
Forumsveranstaltung überfordern würde, wurde das Thema
auf die Untermenge der optischen Keramiken beschränkt.
Diese, nicht zu verwechseln mit Glaskeramiken, zeigen
eine hohe optische Transparenz, sind also rein äusserlich
von hochwertigen optischen Glasscheiben nicht zu unterscheiden. Sie zeigen aber neben den für Keramiken typisch
guten mechanischen und thermischen Eigenschaften auch
weitere, für den Bau von Optikinstrumenten interessante
optische Werte. Erwähnenswert sind hohe Brechzahlen,
aussergewöhnliches Dispersionsverhalten und vor allem
eine nutzbare Transmission vom visuellen bis in den 5-6
μm Spektralbereich, während Gläser nur bis etwa 2 μm
eingesetzt werden können. Gerade für medizinische Anwendungen mit dem Erbiumlaser bei 3 μm sind somit neue
Möglichkeiten denkbar.
Fabrication & characterisation of transparent ceramics for
novel applications, E. Pawlowski, Schott AG
About 20 years ago the first development of transparent ceramic started, finally achieving poly-crystalline ceramic materials for laser and optical applications. It was demonstrated,
that ceramic materials could overcome the main technical problem of light scattering. The established nano-powder vacuum
sintering process at SCHOTT shows good potential for mass
fabrication of multi-composite ceramic materials with different
dopant concentrations. In comparison to conventional transparent materials optoceramics offer further benefits, which lead to
a multiplicity of new applications like optical, laser, solid state
lighting or scintillation. Apart from better mechanical properties
and special optical properties, higher rare-earth doping levels
than single crystals can be achieved, which lead to a higher
conversion efficiency combined with small temperature and
concentration quenching effects. In our talk we will discuss the
fabrication process, the realized materials and the different applications of optoceramics.
Teilnehmerkreis und Symposiumsablauf
Die Veranstaltung wurde am 24. November 2011 zusammen mit der EMPA an ihrem Standort in Dübendorf durchgeführt. Die Organisatoren waren J. G. Bednorz / IBM, B.
Braunecker / SATW, P. Gröning & T. Graule / EMPA und H.
P. Herzig / EPFL. Die 30 Teilnehmer kamen von Ceramet,
EMPA, EPFL, ETHZ, Fisba, IBM, Lasag, Leica Geosystems,
Lonza, Metoxit, Micos, RUAG Space, Schott Forschungszentrum Mainz, Schott Schweiz, Silitec, Swissoptic, SwissLaserNet, Trumpf und Uni Bern. Das Symposium war zweiteilig gegliedert. Nach sechs einführenden Kurzreferaten
wurde in der Teilnehmerrunde diskutiert, welche Auswirkungen die Ergebnisse für die Schweiz haben könnten?
OC materials for lens design, B. Braunecker, SATW
Based on the preliminary optical data of various prototypes of
Schott Optoceramics (large refractive index, large anomalous
dispersion, speckle free transmission, etc.), their impact on the
design of optical systems for imaging, projection, medicine,
space, etc. will be discussed.
Abstracts der Referate
CNC machined optics, B. Reiss, Swissoptic AG
Swissoptic as a leading manufacturer of advanced optical components and systems will report about the surface treatment
of glass and ceramic optics with modern CNC machines and
other deterministic technologies. One exciting example is the
production of monolithic components, i.e. multifunctional components out of one piece of glass.
The challenge of failure free nanopowder processing,
T. Graule, EMPA
Aggregate free synthesis and agglomerate free processing of
nanopowders is achieved by advanced powder synthesis as
well as colloidal processing techniques. The main issue is to
overcome Van der Waals attraction forces by surface treatment
and high energy dispersion techniques. Different approaches to
solve the problem of aggregation and especially agglomeration
are demonstrated.
Thematische Strukturierung
Die Referate wurden in drei Blöcken präsentiert. Im ersten
Teil berichtete E. Pawlowski / Schott über den neuesten
Stand der Herstellung von Schott-Opto-Ceramic Prototypen SOC. Anschliessend B. Reiss / Swissoptic über Ergebnisse bei der Oberflächenbearbeitung verschiedener
SOC - Proben mit modernen CNC-Maschinen und schliesslich B. Braunecker (früherer Entwicklungsleiter - Optik bei
Leica Geosystems), welche neuen Optiksysteme denkbar
wären, wenn es die Materialien kommerziell gäbe. Im zweiten Teil erläuterte T. Graule / EMPA die hohen Ansprüche
und die komplexen Abläufe bei der Materialherstellung,
während A. Studart / ETHZ über neueste Forschungsergebnisse mit multifunktionalen Keramiken berichtete. Im dritten
Teil referierte J. G. Bednorz über eine neue und Aufsehen
erregende Methode aus Japan, bei der das zu dotierende
Keramikmaterial dünne Polymerfolien sind, die interessante
optische Eigenschaften zeigen, aber vermutlich auch für
andere Anwendungen im Solarbereich oder für Batterien
geeignet sein könnten.
Magnetic control of non-spherical ceramic particles in fluid
suspensions, André R. Studart, Complex Materials, Department of Materials, ETH Zürich
We present a method to deliberately control the orientation of
non-spherical nonmagnetic ceramic particles in fluid suspensions using magnetic fields as low as 1 milliTesla. To achieve
magnetic response, the non-spherical particles are coated with
minor contents of magnetic nanoparticles (<0.01 Vol %). This
simple approach might be used for the preparation of polycrystalline ceramics and composite materials with anisotropic optical, electrical, magnetic and mechanical properties.
Super hybrid materials, J. G. Bednorz, IBM
We will present a new method, developed by T. Adschiri (Tohoku University, Sendai, Japan). By using supercritical fluids from
metal salts and organic molecules, oxide nanoparticles can be
produced with an organic modified surface. These organic-inorganic hybrid nanocrystals, having a high affinity to organic
solvents and polymers, can be used to produce flexible ceramic
films with a high filling factor. So far flexible superhybrid materials with high refractive index, high thermal/low electrical conductivity or magnetic particles could be manufactured, showing
the high potential of the new fabrication method.
Fazit
Die Veranstaltung zeigte, dass der vorgestellte Prozessansatz, der höhere Dopingraten des zu Nanopulver verarbeiteten Trägermaterials mit "intelligenten" Fremdatomen wie
Seltenen Erden ermöglicht, nicht nur zu verbesserten ak29
SPG Mitteilungen Nr. 37
tiven (Laser-) und passiven (Linsen-) Optiksystemen führt,
sondern auch zu höheren Effizienzen bei Röntgendetektoren und LED-Lichtquellen. Die erforderlichen technischen
Herstell- & Bearbeitungsprozesse sind zweifelsohne noch
herausfordernd, aber mit dem in der Schweiz vorhandenen
Wissen bei EMPA und den teilnehmenden Firmen durchaus
machbar.
Die an den ETHs betriebene Forschung an multifunktionalen Werkstoffen ist höchst aktuell, da durch geeignete
Behandlungsmassnahmen Keramiken nicht nur wie Halbleiter in ihren photonischen Eigenschaften eingestellt werden können, sondern zusätzlich noch in den mechanischthermischen Parametern. Schliesslich wies die von J. G.
Bednorz aufgezeigte Methode der Massenproduktion dotierter Polymere auf eine kostengünstige Mannigfaltigkeit
an Anwendungen hin.
Die Veranstaltung wurde von den Teilnehmern mehrheitlich
mit "sehr gut" beurteilt und scheint somit einem Bedürfnis
entsprochen zu haben. Während die Industrievertreter die
Informationen über die Technologiefortschritte begrüssten,
bekamen die Hochschulvertreter in der Diskussionsrunde
wertvolle Hinweise über mögliche Anwendungsgebiete. Es
zeigte sich, dass verschiedene Firmen sich bilateral über
ihre Intentionen und Fortschritte austauschen wollen, und
es wurde von nahezu allen Teilnehmern der Wunsch nach
einer Diskussionsplattform und einer Folgeveranstaltung
geäussert.
Progress in Physics (29)
Understanding exchange bias in thin films
Miguel A. Marioni, Sara Romer, Hans J. Hug 1
Empa, Swiss Federal Institute for Materials Testing and Research, CH-8600 Dübendorf
1
Also at: Institute of Physics, Universität Basel, CH-4056 Basel
Every computer hard-drive and
many magnetic sensors contain
a thin-film device using the GMR
or TMR effect. In it, the resistance
from a stack of thin films is made
to depend on the relative orientation of different magnetic layers’
magnetization, of which one serves
as a reference and retains its direction. Fixing the magnetization is accomplished with exchange-bias.
Not surprisingly, the effect has received much attention throughout
the history of magnetic recording
and sensor design. Perhaps it is a
surprise, then, that so much remains
unknown about exchange-bias after
half a century since its discovery.
(a)
(b)
(c)
M(H)
Hex
AF
Mshift
H
Pt
CoO
×20
F
Pt
Si
2 nm
Figure 1: (a) Schematic hysteresis loop of an exchange-biased thin magnetic film. (b) Thin film
multilayer structure with perpendicular magnetization used for MFM studies of exchange bias.
(c) High resolution TEM image of the film structure of (b), highlighting the CoO layer (black
arrow) and one grain boundary (white arrow).
distinct ways and an interpretation of UCS measurements
must take this into account.
Principles of the exchange bias effect
Exchange-biasing manifests macroscopically as a lateral
shift of size Hex of the hysteresis loop (Fig. 1 (a); occasionally there is an accompanying vertical shift Mshift as well.). It
occurs if a sample with at least one ferromagnet (F) / antiferromagnet (AF) bilayer (e.g. in Fig. 1 (b)) is cooled through
the Néel temperature (TN) of the antiferromagnet. It is generally believed that (local) magnetization of the ferromagnet
(F) layer (locally) generates pinned uncompensated spins
(pUCS) in the AF layer that are coupled to the F layer. An
obstacle to understanding the exchange bias effect is that
only a subset of the UCS (those pinned, and coupled to
the ferromagnet) are responsible for it [1]. The experimental method and preparation may affect these subsets in
Experimental Methods to measure uncompensated
pinned spins
Reflectometry experiments using polarized neutrons or
circularly polarized X-rays as probes have been used to
access UCS sub-systems and to map out their thickness
distribution. Both methods fit proposed model descriptions
of these distributions to the experimental data. Neutronbased techniques can unambiguously determine the relative orientation of the UCS of the various sub-systems and
the F-spins. To accomplish this X-ray-based experiments
require, in addition, specifying magneto-optical constants
of the atomic species carrying the spin in the AF. Recent
30
Communications de la SSP No. 37
results have also stressed the influence on XMLD (X-ray
Magnetic Linear Dichroism) signals of the orientation of AF
spins relative to the crystallographic axes.
Reflectometry techniques cannot, however, reveal the
lateral distribution of UCS. This very important aspect of
exchange bias characterizations is accessible with other
(complementary) techniques. Among these, photoemission
electron microscopy (PEEM) with circular and/or linearly
polarized X-rays has revealed a correlation between AF domains and F-domains, the formation of new chemical phases at the AF/F interface with magnetic moments parallel to
those of the F, and induced ferromagnetic moments at the
AF/F interface. But PEEM microscopes have to-date not
attained lateral resolutions on the length scale of grainssizes of typical polycrystalline AF materials, important for
applications. Note that PEEM experiments require the applied magnetic field to be zero or near-zero, and accordingly cannot distinguish pinned from non-pinned UCS of
the AF directly. In fact, only a small part of the net moment
induced locally by the F in the AF consists of pinned UCS,
which are difficult to isolate from the rest with present-day
PEEM sensitivities.
contrast arising from the stray field of a domain pattern in a
ferromagnetic thin film with perpendicular magnetization is
proportional to the z-component of the magnetic moment
areal density [2]. This allows a first estimate of the contrast
expected for a domain pattern of pinned uncompensated
spins imprinted by a corresponding pattern of ferromagnetic domains. In our recent work [2] the MFM contrast
measured above an up/down domain pattern in a CoPt ferromagnetic multilayer was 46 Hz (Fig. 2 (a)). From the magnetization of the CoPt-multilayer and its thickness a total
magnetic moment areal density of mFz/A= MCoPt tCoPt = 622
kA/m × 22 nm = 1.37 · 10-2 Am2/m2 is found. Likewise an
areal moment density of 4.48 · 10-4 Am2/m2, corresponding
to a fully uncompensated CoO AF, would thus generate a
frequency shift of 1.5 Hz. Our MFM can easily detect ±0.05
Hz in a reasonable measurement bandwidth of 100 Hz, corresponding to a scan speed of about 1s/line in a 256 pixel
line. This means that the corresponding ±1.49 · 10-5 Am2/m2
are detectable, and hence also about ±3% of a fully uncompensated monolayer.
Assessing the number of pinned uncompensated spins
by MFM
Not only can MFM image fractions of uncompensated AF
spins but it can also be used in applied homogeneous
fields. These do not generate a force on the magnetic tip
and thus do not give rise to MFM contrast. One can therefore study the evolution of the F-domain pattern in external
fields as shown Fig. 2 (a) and (b) (In prior work up to 7 T
were applied [4]).
MFM however lacks the element-specificity of XMCD
methods, so it cannot distinguish directly between different
sources of the stray field, i.e. generated by different atomic
species. The contrast observed in the data shown in Fig. 2
(a) and (b) arises predominantly from the stray fields emanating from the up/down domain pattern of the F-layer and
a small contribution from the imprinted local uncompensated AF moments. However, magnetic stray fields generated
the F-layer roughness, as well as by local variations of its
thickness or saturation magnetization, could also generate
a small MFM contrast. Topography-induced variations of
the van der Waals force occurring when the tip of the MFM
scans in a plane parallel to the average slope of the sample
provide yet another contribution to the measured contrast.
Modeling shows that from these last contributions to contrast only the van der Waals force-mediated topography contribution is relevant.
It leads to the grainy appearance of the
F-domain contrast (Fig. 2 (a)).
In contrast to XMCD-PEEM, XMCD (X-ray Magnetic Circular Dichroism) holography is a lens-less imaging method and hence allows the application of arbitrary magnetic
fields. Recently, element-selective soft x-ray holography
and spectroscopy measurements have been used to study
the evolution of domains in ferromagnetic multilayer of
[Pt(1.8nm)Co(0.6nm)]×8 on a Mn80Ir20(5nm) antiferromagnetic
layer [2]. Element-specific magnetometry revealed uncompensated AF magnetic moments on the Mn and allowed to
estimate that about 10% of these moments are pinned and
thus are relevant for the exchange bias effect. However, no
magnetic contrast could be observed at the Mn L3 edge, so
the imaging of the pattern of uncompensated and pinned
uncompensated Mn moments was not achieved.
A different technique to gain access to the UCS of a system
is magnetic force microscopy (MFM). Operated in vacuum,
MFM typically measures shifts in the resonance frequency of a cantilever outfitted with a magnetic tip. These are
proportional to the magnetic field gradients to which the
tip is exposed. Therefore an MFM investigation of sample
properties requires a sample with suitable domains generating stray field [3]. In a rough approximation, the MFM
(a)
(b)
H=0
46 Hz contrast
ntrast
(c)
200 mT
300 mT
35 Hz contrast
ontrast
4.4 Hz contrast
Figure 2: High resolution MFM images of the sample of Figure 1 (b) and (c) obtained at
constant average tip-sample distance of 13.0±0.5 nm. (a) Large contrast obtained in
zero applied fields. (b) In a field of 200 mT the bright domains retract. (c) The ferromagnetic layer is saturated at 300 mT. A weak and grainy contrast is retained. This contrast
remains unaltered in fields of at least 7 T. A white arrow across Figs. (a) – (c) indicates a
particular spot of the film where the retracting bright domain leaves a dark mark in the
area it covered at zero field.
31
If the F-layer is saturated by applying a
sufficiently strong external field, it does
no longer generate an MFM contrast.
One can easily understand this by noting that the stray fields generated by the
magnetic poles of the top and bottom
surface compensate. In this situation
the only remaining source of contrast is
the pattern of pinned uncompensated
AF moments. Note that if the other contrast contributions cannot be neglected,
the difference of two consecutive MFM
measurements performed in positive
SPG Mitteilungen Nr. 37
and negative saturation fields will solely contain the contrast contribution of the pinned UCS moments [4].
as the ferromagnetic domains evolve, Fig. 2. Dark areas
correspond to parallel tip and sample magnetization; i.e.
there is an attractive force and negative frequency shift.
Conversely, bright areas correspond to the antiparallel orientation and positive frequency shift. F-domains are clearly
visible in Figs. 2 (a) and (b), generating a contrast of several
tens of Hz. As expected, the area of the bright domains
(magnetization opposite to the applied field) diminishes as
fields are applied parallel to the dark domain magnetization,
as e.g. Fig. 2(b) for 200 mT. Consistent with the saturation
Quantitative MFM on exchange-biased systems
It is now possible to ascertain the exact relation between
pinned uncompensated spins and exchange bias by looking at the evolution of ferromagnetic domains over the underlaying pattern of pinned uncompensated spins [5]. For
example a film of Pt(2nm)/CoO(1nm)/Co(0.6nm)/ [Pt(0.7nm)
Co(0.4nm)]x20/Pt(20nm)/Si (Fig. 1 (b) and (c)) can be seen
(a)
0m
Ta
pp
lied
AF UCS
under
blue F domains
fie
ld
(c)
AF UCS
under
yellow F domains
F
-10
0%
pin
UC
S
10
0%
Project F-domain
contours (white)
onto AF UCS
Increase applied field
20
0m
Ta
pp
lied
fie
ld
ave. pinUCS (% AF ML)
(b)
AF
(d)
Figure 3: Quantitative analysis of the MFM measurements of the
multilayer of Figures 1 – 2. (a) Stack of MFM measurements for
zero applied field following the buildup of the magnetic multilayer.
The top surface is the MFM measurement of F domains’ contrast.
Underneath is the interface with the AF, comprising a distribution of UCS, aligning antiparallel to the F-orientation. Because the
UCS relevant for exchange bias are the pinned ones, they can be
determined from the MFM measurement of a saturated ferromagnet (Figure 2 (c)) and the tip-transfer function [7], as indicated
20
10
0
-10
-20
-30
0
100
200
300
H (mT)
in the scale bar in the Figure. White contours are included in this
layer to highlight the position of F-domains. (b) Results for 200 mT
following the format of (a). (c) Pinned UCS density disaggregated
from either F-domain, at 0 and 200 mT applied fields. The average
(negative) magnitude of pinned UCS is larger under the retracted
yellow F-domains than their zero field counterparts. (d) Graph showing the correlation between pinned UCS density under a domain
and the applied field.
32
Communications de la SSP No. 37
of the ferromagnet the bright domains have disappeared
at 300 mT, Fig. 2 (c). At this and larger fields (up to 7 T) the
MFM data reveals a rather irregular pattern with contrast of
only 4.4 Hz. Cooling the F/AF system with the F in different
initial domain states reveals that the shape of the patterns
observed after saturation are governed by the structure of
the initial F-domains.
In Figure 3 (c) small regions can be seen with parallel pinned
UCS-F domain alignment at zero field (red arrows). The retracting F-domains avoid these regions as they reconfigure
in response to the applied field.
In other words, at least in the CoO (and MnIr as shown in
[2]) Co/Pt perpendicular system pinned UCSs coupling antiparallel to the F magnetization stabilize its orientation, i.e.
they are biasing, whereas pinned UCSs oriented parallel to
the F magnetization have the opposite effect, i.e. they are
anti-biasing.
These results are a direct observation of the stabilizing effect of (antiparallel) pinned UCS on F domains, and show
that a higher pinned UCS density leads to a stronger F domain pinning, i.e. a higher EB effect.
In the same way that the saturated F does not produce a
stray field, the uncompensated AF spins which rotate with
the F-domains will not be imaged at saturation. The main
contrast is thus due to pinned UCS [6]. Using the response
function of the MFM tip according to quantitative MFM
methods [6] one can obtain the areal moment of pinned
uncompensated spins (more specifically the z-component
of the areal moment of the pinned UCS projected onto a
virtual F/AF interfacial plane) from the Df pattern (Fig. 2 (c)).
The result can be seen in Fig. 3 (a). At the AF-F interface a
strikingly inhomogeneous distribution of the pinned UCS
is revealed. TEM images of the films (Fig. 1(c)) show columnar grains in the film with sizes of the order of 10 nm,
placing the observed pinned UCS variations on the same
length scale. This pinned UCS distribution also represents
an inhomogeneous distribution of ‘‘pinning’’ centers for
F-domain motion, leading to the commonly observed EBinduced increase in coercivity.
Figures 3 (a) and (b) also show the F-domain contours
(white lines) at different fields overlaid to the pinned uncompensated AF moment pattern that biases them. From them
we see that the pinned UCS in the area initially covered by
bright F domains (Fig. 1) is predominantly negative [blue
in Figs. 3 (a) and (b)], whereas the area initially covered by
dark F domains (Fig. 1) is predominantly positive [yellow
in Figs. 3 (a) and (b)]. This local antiparallel alignment between the F magnetization and the pinned UCS suggests
antiferromagnetic coupling across the F/AF interface and is
consistent with earlier work [2,6,7]. Because the local alignment is antiparallel to the local cooling field, it can only be
the result of exchange coupling.
Notice the existence of isolated regions of pinned UCS that
do not follow the above trend. They are oriented parallel to
the (initial) adjacent F-magnetization, and seem to be circumscribed to areas of the size of single grains of the film
(cf. Fig. 1 (c)).
More insight can be gained from a quantitative evaluation
of the data just discussed.
Concluding remarks
The density of pinned UCS found by MFM agrees well with
work on polycrystalline Py/CoO samples estimating the
pinned UCS at about 10% of a 1.1 monolayer-thick layer
of interfacial Co2+ spins. A decreasing magnetic moment of
the FM layer near the interface may explain the somewhat
smaller density of pinned UCS observed there. But the high
density of pinned UCS requires that the average coupling
strength between the pinned UCS and F-spins be much
smaller than previously expected, in order to explain the
rather small exchange bias field.
Without an exhaustive theoretical analysis of the pinned
UCS coupling strength and possible variations thereof, we
point out that the interface between the AF and the F very
likely differs from a chemically sharp interface across which
the system goes from F to AF, on account of interdiffusion
and interface reconstruction. A similar reconstruction ought
to be expected in the CoO/Co interfaces discussed here
and may lead to a structurally and chemically disordered
interfacial phase, explaining the higher density of pinned
UCS and their weaker coupling to the F-spins. Furthermore
frustration, as found in spin glass systems, may also lead to
weak or indirect coupling between AF UCS and the F-layer.
Yet a weak coupling may be a necessary condition for the
UCS AF moments to remain pinned to the AF-lattice rather
than rotate with the F-moments.
Exchange coupling between different AF grains across their
grain boundaries could lead to frustration of the magnetic
orientation over grain-size areas, giving rise to the observed
anti-biasing effect. Further work to address this issue is under way.
One can compute the average pinned UCS density (data
from Figs. 3 (a) and (b) for the areas under the F-domains,
i.e. delimited by the white contours of the figures, as shown
in Figs. 3 (c). Under the initial yellow and blue F-domains
the average pinned UCS density is ±21.8% of a fully uncompensated monolayer of AF spins. As a magnetic field is
applied parallel to the blue F-domains, they expand at the
expense of the yellow F-domains. Over the area covered
by the retracted yellow F-domains the average pinned UCS
is more negative than before the field was applied. Figure 3
(d) shows the average densities of UCS under each domain
type as a function of the applied field. A roughly proportional relation between the applied field and the average
pinned UCS density under the surviving yellow F-domains
is apparent.
[1] I. Schmid, et al. Europhys. Lett. 81, 17001 (2008).
[2] C. Tieg et al. Appl. Phys. Lett. 96, 072503, (2010).
[3] N. R. Joshi, et al. Appl. Phys. Lett. 98, 082502 (2011).
[4] P. Kappenberger, I. Schmid & H. Hug., Adv. Eng. Mater. 7, 332
(2005).
[5] I. Schmid, et al. Phys. Rev. Lett. 105, 197201 (2010)
[6] P. J. A. van Schendel, H. J. Hug, B. Stiefel, S. Martin & H.-J.
Güntherodt. J. Appl. Phys. 88, 435 (2000).
[7] P. Kappenberger, et al. Phys. Rev. Lett. 91, 267202 (2003).
33
SPG Mitteilungen Nr. 37
The legacy of Martin Gutzwiller
Last November, the Faculty of Science of the University of
Fribourg awarded the doctor honoris causa to Martin Gutzwiller, with a threefold motivation: His outstanding contributions to theoretical physics, his active interest for science
in general and his relations to Fribourg. Reason enough for
emphasizing the eminent role Gutzwiller played during the
last half century, especially in the two still very active research areas of quantum chaos and correlated electrons, as
described in some detail below. Special thanks to Michael
Berry for his profound analysis of Gutzwiller’s pioneering
work in "quantum chaology".
admits having received “a marvelous education in early
field theory”, but at the same time having been frustrated
because the problem posed by Pauli could not be handled
in a satisfactory way. Thus he pleads for coming back to
"down-to-earth physics", instead of "chasing an elusive
goal on the basis of abstract models".
After having received his diploma, Martin Gutzwiller worked
during one year as an engineer in microwave transmission
at Brown Boveri in Baden. In 1951 he moved to the US,
where he spent most of the time since. At the University
of Kansas he made his Ph. D. studies under the guidance
of Max Dresden, on "Quantum Theory of Fields in Curved
Space". From 1953 to 1960 he worked on geophysics in a
laboratory of Shell in Houston, Texas. A position at the IBM
Zurich Research Laboratory, then still in Adliswil, brought
him back to Switzerland for three years, but subsequently
he settled definitely down in New York. He remained a researcher at IBM, from 1963 to 1970 at the Watson Laboratory and from 1970 to 1993 in Yorktown Heights. He was at
the same time Adjunct Professor in Metallurgy at the Columbia University. After his retirement from IBM he became
an Adjunct Professor at the Yale University.
Martin Gutzwiller was born
1925 in Basel. His father
was an internationally known
professor of law, from 1921
to 1926 at the University of
Fribourg, from 1926 to 1936
at the University of Heidelberg and then, after having escaped with his family
from Germany because of
the harassment by the nazis,
again in Fribourg from 1937
to 1956. Martin passed his
first school years in Heidelberg. Back to Switzerland,
Martin Gutzwiller ca. 1951/52 he received his further education in Trogen and at the
Collège Saint Michel in Fribourg, where he passed the final
two years of gymnasium. In 1944 he started studying physics at the University of Fribourg, but then he enrolled at the
ETH in Zürich, where he received the diploma in 1949. His
diploma work on the magnetic moment of nucleons with
vector-meson coupling, supervised by Wolfgang Pauli, undoubtedly had a strong impact on his view of physics. 45
years later, in a letter to Physics Today (August 1994), he
Martin Gutzwiller has published about 40 papers, most of
them alone. He received prestigious prizes, such as the
Dannie Heinemann prize of the American Physical Society
(1993) or the Max-Planck Medal of the German Physical
Society (2003). His international recognition is also well
documented by four issues of Foundations of Physics
(2000/2001), published at the occasion of his 75th birthday. It is worth mentioning that his research activities were
broader than quantum chaos and correlated electrons, they
included such diverse topics as dislocations in solids, the
quantum Toda lattice and the ephemerides of the moon.
Dionys Baeriswyl, Uni Fribourg
Martin Gutzwiller and his periodic orbits
Michael Berry, H H Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK
In the 1970s, physicists were made aware, largely through
the efforts of the late Joseph Ford, that classical hamiltonian mechanics was enjoying a quiet revolution. The traditional emphasis had been on exactly solvable models, with
as many conserved quantities as degrees of freedom, in
which the motion was integrable and predictable. Examples
are the Kepler ellipses of planetary motion, and the simple
pendulum: 'as regular as clockwork'. The new research,
incorporating Russian analytical mechanics and computer
simulations inspired by statistical mechanics, revealed that
most (technically, 'almost all') dynamical systems behave
very differently. There are few conserved quantities, and
motion, in part or all of the phase space, is nonseparable
and unpredictable, that is, unstable: initially neighbouring
orbits diverge exponentially. This is classical chaos.
It was quickly realised that this classical behaviour must
have implications for quantum physics, especially semiclassical physics, e.g. for the arrangement of high-lying
energy levels and the morphology of eigenfunctions. The
study of these implications became what is now called
quantum chaos (though I prefer the term quantum chaology). This is an area of research in which Martin Gutzwiller
made a seminal contribution, described in the following,
which I have adapted from a speech honouring his 70th
birthday. Since a substantial part of my own scientific life
has been devoted to the development and application to
Martin's ideas, I won’t attempt to be detached.
Martin published the last of his series of four papers [1-4]
on periodic orbits exactly forty years ago. I encountered
them at that time, while Kate Mount and I were writing our
review of semiclassical mechanics. That was prehistoric
semiclassical mechanics: before catastrophe theory demystified caustics, before asymptotics beyond all orders
lifted divergent series to new levels of precision, and above
all before we knew about classical chaos.
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Communications de la SSP No. 37
Of Martin's series of papers, the most influential was the
last one [4], containing the celebrated 'Gutzwiller trace formula'. That was a tricky calculation, based on the Van Vleck
formula for the semiclassical propagator, giving the density
of quantum states (actually the trace of the resolvent operator) as a sum over classical periodic orbits. In particular,
Martin calculated the contribution from an individual unstable periodic orbit. Nowadays we can see this as one of the
'atomic concepts' of quantum chaology, but in those days
chaos was not appreciated. But he emphasized the essential novelty of his calculation in a similar way: it applies even
when the classical dynamics is nonseparable. I'm rather
proud of what we wrote at the beginning of 1972, as the
last sentence of our review:
"Finally, the difficulties raised by Gutzwiller's (1971) theory
of quantization, which is perhaps the most exciting recent
development in semiclassical mechanics, should be studied deeply in order to provide insight into the properties of
quantum states in those systems, previously almost intractable, where no separation of variables is possible."
described when we learned that William Miller wanted to
visit us in Bristol, to talk about his new work on periodic
orbits. We convinced ourselves that this must be the same
as ours, and laboured day and night (up a ladder, actually,
because Michael was helping me paint my new house) to
get our paper written and submitted before he arrived. We
were foolish to panic, because William's work was completely different.
An awkward feature of stable orbits, recognized clearly by
Martin in those early days, was that focusing occurs along
them, leading for certain repetition numbers and stability indices to divergences of the contributions he calculated, associated with bifurcations. That awkwardness was removed
in 1985 by Alfredo Ozorio de Almeida and John Hannay,
who applied ideas from catastrophe theory that had come
into semiclassical mechanics in the 1970s. Their development of Martin's formula became popular much later, when
the features they predicted could be detected numerically.
In the early 1970s, Ian Percival made us aware of the
amazing developments in classical mechanics by Arnold
and Sinai, before chaos became popular. Percival insisted
that semiclassical mechanics must take account of chaos.
Later, we learned more about chaos from Joseph Ford. Of
course Martin had paved the way with his trace formula for
unstable orbits.
The trace formula could be approximated by taking just one
periodic orbit and its repetitions. This led to an approximate 'quantization formula' that gave good results when
applied to the lowest states of an electron in a semiconductor, whose mass depended on direction. I am referring
to the birth of Martin's treatment of the anisotropic Kepler
problem [5].
A persistent question was whether the formula could generate asymptotically high levels for a chaotic system. My
opinions fluctuated. In 1976 I thought it could not, arguing
that long orbits - required to generate the high levels - were
so unstable that the Van Vleck propagator would not be
valid for them. Instead, I thought (using ideas developed by
Balian and Bloch) that periodic orbits could at best describe
spectra smoothed on scales that were large compared with
the mean spacing – but still classically small, so that some
detail beyond the Weyl rule was accessible, though still not
individual levels. This question is still not settled definitively,
but my pessimistic opinion was changed by two developments.
For a few years, his calculation was widely misinterpreted
(among the ignorant it is misinterpreted even today) as implying a relation between the individual energy levels and
individual periodic orbits of chaotic systems. One might
call this the 'De Broglie interpretation' of the trace formula:
that there is a level at each energy for which the action of
a periodic orbit is a multiple of Planck. This is nonsense:
the simplest calculation shows that the number of levels is
hopelessly overestimated – in a billiard, for example, there
is an 'infra-red catastrophe', that is, the prediction of levels
at arbitrarily low energies.
Martin's papers quickly inspired others. In 1974, Jacques
Chazarain showed that the trace formula could be operated
'in reverse', so that a sum over energy levels generated a
function whose singularities were the actions of periodic
orbits. This was exact, not semiclassical, and led (often
unacknowledged) to what later came to be called 'inverse
quantum chaology' and 'quantum recurrence spectroscopy'. In 1975 Michael Tabor and I generalized some of the
results in the first of Martin's semiclassical papers [1] to
get the general trace formula for integrable systems, where
the periodic orbits are not isolated but fill tori. In nuclear
physics, similar formulas had been obtained by Strutinsky
in the context of the shell model. Tabor and I used our result
to show that the level statistics in integrable systems are
Poissonian - more about that later. William Miller and André
Voros resolved a puzzle about the application of the trace
formula for a stable orbit: by properly quantizing transverse
to the orbit, they restored the missing quantum numbers;
then Martin's single-orbit quantization rule makes sense,
as the 'thin-torus' limit of Bohr-Sommerfeld quantization.
The first was energy level statistics. In the 1970s, following
a suggestion from Balazs Gyorffy, I imported from nuclear
physics the idea that random matrices could be relevant in
the quantum mechanics of chaos. The first application of
this suggestion was not to chaotic systems at all, but to integrable systems, where it was shown – as I just mentioned
– that the levels are not distributed according to randommatrix theory. That work inspired Allan Kaufman and Steven McDonald to the first calculation of level spacings for a
chaotic system: the stadium. Then I did the same for Sinai's
billiard. In those days we were fixated on the spacings distribution. My way of deriving level repulsion was a generalization of Wigner's: through the codimension of degeneracies. This gave the same result as random-matrix theory for
small spacings, and explained the differences between the
different ensembles, but gave no clue as to why randommatrix theory worked for all spacings, and why it was connected with classical chaos.
Then came Oriol Bohigas and Marie-Joya Giannoni and
Charles Schmit. What they did, in the early 1980s, was
simple but very important. They repeated the calculations
that Kaufman and McDonald and I had done, for the same
Probably Martin didn't realize that his formula was so
fashionable at that time that it induced a certain hysteria.
Michael Tabor and I were quietly finishing the work I just
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SPG Mitteilungen Nr. 37
this defect is shared by the formally exact counterpart of
the formula for billiards with constant negative curvature,
namely the Selberg trace formula. And later Frank Steiner
taught us that trace formulas can sometimes converge conditionally, in ways depending delicately on the topology of
the orbits (expressed as Maslov phases). Eventually these
concerns about convergence led naturally to the study of
zeta functions. The idea there is to find a function where the
energy levels are zeros, rather than steps or spikes as in the
density of states. The grandparent of all these objects is
Riemann's zeta function of number theory. I learned its possible relevance to quantum chaology from Oriol Bohigas,
and also from Martin's semiclassical interpretation of the
Faddeev-Pavlov scattering billiard, where Riemann's zeta
function gives the phase shifts [6, 7]. It is amazing that Martin had already realized the connection with zeta functions
in his 1971 paper. He wrote:
"This response function is remarkably similar to the socalled zeta functions which mathematicians have invented
in order to survey and classify the periodic orbits of abstract
mechanical systems."
(He cited Smale). And in 1982 Martin explicitly wrote a
semiclassical zeta function of the kind we consider today,
and used it in conjunction with some tricks from statistical
mechanics to sum the periodic orbits for the anisotropic
Kepler system [7, 8].
systems and using the same numerical methods, but instead of focusing on the one statistic of the level spacing
they appreciated that the random-matrix analogy is much
broader: it predicts all the spectral statistics, in particular
long-range ones. They calculated one of these: the spectral
rigidity (equivalent to the number variance).
Their observation was enormously influential. In particular,
it was central to my construction in 1985 of the beginnings
of the semiclassical theory of spectral statistics from Martin's atoms: the periodic orbits. Another crucial ingredient in
this was also a development of periodic-orbit theory: the inspired realization by John Hannay and Alfredo Ozorio de Almeida that the Gutzwiller contributions of long orbits obey
a sum rule whose origin is classical and whose structure is
universal - that is, independent of details. Pure mathematicians (Margulis, Parry, Pollicott) had found similar rules more general in that they applied to dissipative as well as
hamiltonian systems, but also more restricted in that Hannay and Ozorio's theory applied also to integrable systems
(where Tabor and I had found their particular result in 1977
but failed to appreciate its general significance). Thus periodic orbits were able to reproduce key formulas from random-matrix theory, and random-matrix universality found a
natural explanation as the inheritance by quantum mechanics of the classical universality of long orbits. There was
more: the periodic orbit theory of spectral statistics showed
clearly and simply why and how random-matrix theory must
break down for correlations involving sufficiently many levels. There were misty mathematical aspects – now being
clarified – of those arguments, but the formulas were not
misty, and were the first step in convincing me that long
orbits in Martin's trace formula were meaningful.
A crucial ingredient turned out to be the Riemann-Siegel
formula, that makes the sum over integers for the Riemann
zeta function converge. I realized this in 1986, and later developed the idea with Jon Keating [9]; we were helped by
André Voros's precise definitions of the regularized products in these zeta functions. The result was an adaptation
of the trace formula to give a convergent sum over periodic
orbits, soon employed to good effect by Keating and Martin
Sieber [10] (see the figure). A related idea was the invention
of cycle expansions by Predrag Cvitanovic and Bruno Eckhardt; in these, essential use is made of symbolic dynamics to speed the convergence of the sum over orbits. This
application of coding to semiclassical mechanics was also
originally Martin's idea: he used it in the 1970s and early
1980s to classify and then estimate the sum over the orbits,
again for the anisotropic Kepler problem [7, 8].
The second step sprang from the realization - increasingly
urgent in the early 1980s - that the series of periodic orbits
in the trace formula does not converge. The cause was realized by Martin in 1971 [4]:
"Even more serious is the fact that there is usually more
than a countable number of orbits in a mechanical system,
whereas the bound states of a Hamiltonian are countable."
The failure of the trace formula to converge was emphasized especially by André Voros, who pointed out that
The two applications of Martin's periodic-orbit ideas that I
have just described, to spectral statistics and to zeta functions, were combined by Eugene Bogomolny and Jonathan
Keating. This development, and more recent insights from
Martin Sieber, Fritz Haake and Sebastian Müller, are taking the derivation of random-matrix formulas from quantum
chaology to new levels of sophistication and refinement.
In the mid-1980s, Eric Heller discovered that for some
chaotic systems the wavefunctions of individual states are
scarred by individual short periodic orbits, in ways that depend on how unstable these are. From this came further
extensions of Martin's ideas, to new sorts of spectral series
of periodic orbits, not involving traces, and for Wigner functions as well as wavefunctions.
Quantum spectral determinant (zeta function) for a particle confined between branches of a hyperbola, calculated exactly (dashed curve) and from a renormalized version [9,10] of Gutzwiller's
sum over the unstable classical periodic orbits (full curve); the
energy levels are the zeros, indicated by stars. Reproduced from
[10], with permission.
In spite of all this progress, we are still unable to answer definitively and rigorously the central question Martin posed in
1971 [4]:
"What is the relation between the periodic orbits in the clas36
Communications de la SSP No. 37
sical system and the energy levels of the corresponding
quantum system?"
Of course the trace formula itself is one such relation, but I
am sure that what Martin meant is: how can periodic orbits
be used for effective calculations of individual levels. For
the lowest levels there is no problem, but – and again I
quote from Martin’s 1971 paper "the semiclassical approach to quantum mechanics is supposed to be better the larger the quantum number"
and to reproduce the spectrum for high levels, using even
the convergent versions of the trace formula that are now
available, requires an exponentially large number of periodic orbits. This is a gross degree of redundancy unacceptable to anybody who appreciates the spectacular power
of asymptotics elsewhere. Martin's old ideas continue to
challenge us.
[7] Gutzwiller, M. C.,1982, The Quantization of a Classically Ergodic System Physica D 5, 183-207
[8] Gutzwiller, M. C.,1977, Bernoulli Sequences and Trajectories in
the Anisotropic Kepler Problem J. Math. Phys. 18, 806-823
[9] Berry, M. V. & Keating, J. P.,1992, A new approximation for
zeta(1/2 +it) and quantum spectral determinants Proc. Roy. Soc.
Lond. A437, 151-173
[10] Keating, J. P. & Sieber, M.,1994, Calculation of spectral determinants Proc. Roy. Soc. Lond. A447, 413-437
After graduating from
Exeter and St Andrews,
Michael Berry entered
Bristol University, where
he has been for considerably longer than he has
not. He is a physicist, focusing on the physics of
the mathematics…of the
physics. Applications include the geometry of
singularities (caustics on
large scales, vortices on
fine scales) in optics and
other waves, the connection between classical and quantum physics, and the
physical asymptotics of divergent series. He delights
in finding the arcane in the mundane – abstract and
subtle concepts in familiar or dramatic phenomena:
- Singularities of smooth gradient maps in rainbows
and tsunamis;
- The Laplace operator in oriental magic mirrors;
- Elliptic integrals in the polarization pattern of the
clear blue sky;
- Geometry of twists and turns in quantum indistinguishability;
- Matrix degeneracies in overhead-projector transparencies;
- Gauss sums in the light beyond a humble diffraction
grating.
A few years ago, I refereed an application for research funding for a German-British collaboration. This required me to
comment on the applicants' "timetable for research" and
their "list of deliverables". I wrote "In science there are no
deliverables; researches are not potatoes". Martin Gutzwiller ignored these toxic fashions. What makes him so attractive as a scientist is that he refuses to follow any fashion;
instead, he generates ideas that become the fashion.
References
[1] Gutzwiller, M. C.,1967, The Phase Integral Approximation in
Momentum Space and the Bound States of an Atom J. Math.
Phys. 8, 1979-2000
[2] Gutzwiller, M. C.,1969, The Phase Integral Approximation in
Momentum Space and the Bound States of an Atom II J. Math.
Phys. 10, 1004-1020
[3] Gutzwiller, M. C.,1970, The Energy Spectrum According to
Classical Mechanics J. Math. Phys. 11, 1791-1806
[4] Gutzwiller, M. C.,1971, Periodic orbits and classical quantization conditions J. Math. Phys. 12, 343-358
[5] Gutzwiller, M. C.,1973, The Anistropic Kepler Problem in Two
Dimensions J. Math. Phys. 14, 139-152
[6] Gutzwiller, M. C.,1983, Stochastic behavior in quantum scattering Physica D 7, 341-355
Martin Gutzwiller and his wave function
Dionys Baeriswyl, Département de physique, Université de Fribourg, 1700 Fribourg
Werner Weber, Fakultät Physik, Universität Dortmund, DE-44221 Dortmund
Gutzwiller's work on correlated electrons is mostly concentrated in three papers, written in the time span 1962
to 1964 [1, 2, 3]. A short fourth paper was published a few
years later [4]. In essence, Gutzwiller introduced a variational ansatz, where charge fluctuations are reduced as compared to Hartree-Fock theory, thus quantifying Van Vleck's
qualitative idea of minimum polarity [5].
H = - t / (c i@v c jv + c j@v c iv) + U / n i - n i .
i ,j
(1)
i
where the first term describes electron hopping between
the neighboring sites of a lattice ( c @iv and c iv are, respectively, creation and annihilation operators for electrons at
site i with spin s) and the second term is the interaction,
which acts only if two electrons meet on the same site
( n iv = c @iv c iv ). Quantum chemists had previously used a
similar model for p-electrons in conjugated polymers, but
they had included the long-range part of the Coulomb interaction. Curiously, shortly after Gutzwiller's first paper on the
subject, two publications appeared where the same Hamiltonian (1) is treated, but without reference to Gutzwiller's
work, one by Hubbard [7], the other by Kanamori [8]. One
Historically, electronic correlations were first studied for the
homogeneous electron gas, much less for electrons in narrow bands such as d-electrons in transition metals. A noticeable exception was Anderson's paper on the kinetic origin of antiferromagnetism in transition metal compounds,
where a localized basis of Wannier functions was used [6].
In the same spirit, Gutzwiller wrote down the Hamiltonian
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SPG Mitteilungen Nr. 37
g depends on the electron density n as g = (1 - n)/(1 - n/2).
Therefore, when approaching half filling (n " 1), the electron motion is completely suppressed, and the system is
a Mott insulator. Brinkman and Rice noticed that within the
Gutzwiller approximation the jamming of electrons (for n =
1) occurs at a large but finite value of U and is signaled by
the vanishing of double occupancy [16]. They associated
the critical point with the Mott metal-insulator transition.
However, a closer scrutiny shows that this conclusion is
an artifact of the Gutzwiller approximation. Indeed, for an
exact treatment of the Gutzwiller ansatz (and finite lattice
dimensions) double occupancy remains finite for all finite
values of U. Moreover, the Gutzwiller ansatz itself is of limited validity for large values of U, as seen clearly by comparing it with the exact solution in one dimension.
has to conclude that the three papers [1, 7, 8] were written
completely independently and that the Hamiltonien (1), now
universally referred to as Hubbard model, was in the air,
especially for investigating the problem of correlated electrons in transition metals.
In contrast to Gutzwiller, who did not care too much about
the justification of the model, Hubbard estimated the different Coulomb matrix elements between localized d wave
functions, and he also explained how in transition metals
with partly filled 3d shells and a partly filled 4s shell the selectrons can effectively screen the Coulomb interactions
between d-electrons. The fact, pointed out by Gutzwiller
[3], that the three authors, himself, Hubbard and Kanamori,
obtained qualitatively different results, shows that, despite
of its formal simplicity, the model was – and still is – very
challenging.
Nevertheless, a Mott transition does occur for the Hubbard
model, but in the sense of a topological transition from a
phase with finite Drude weight for small values of U to one
with vanishing Drude weight at large U, in agreement with
Kohn’s distinction between metals and insulators [17]. To
show this in a variational framework 1, we have used a pair
of trial ground states [18], the Gutzwiller wave function W
together with the "inverted" ansatz
Gutzwiller's main contributions to the field of correlated
electrons are his ansatz for the ground state of the Hubbard
model and his ingenious way of handling this wave function.
He starts from the ground state W 0 of the hopping term,
the filled Fermi sea. This would just yield the Hartree-Fock
approximation, which treats neutral and "polar" configurations on the same footing. Thus he adds a projector term,
now called correlator, that reduces charge fluctuations. His
ansatz reads
W = % 61 - ^1 - hh n i - n i .@ W 0
t
Wl = e -hT W 3
where Tt = / (c i@v c jv + c j@v c jv) is the hopping operator, W 3
(2)
i ,j
is the ground state for U " ∞ and h is a variational param-
i
or, written in a different way,
W =e
-gDt
W0
eter. One readily shows that W has a finite Drude weight
and lower energy for small U, while the Drude weight vanishes for Wl , which is preferred for large U. A metal-insulator transition occurs for a value of U of the order of the
band width, in good agreement with Quantum Monte Carlo
results.
(3)
where Dt = / n i - n i . is the number of doubly occupied sites
i
and g is related to Gutzwiller’s parameter  by  = e-g.
So far, we have assumed the Gutzwiller ansatz to be "adiabatically" linked to the filled Fermi sea W 0 , which is the
main reason for the metallic character of W . However, if
we allow for a broken symmetry within W 0 , we may find a
competing ground state with qualitatively different properties. For instance, allowing for different magnetic moments
on the two sublattices of a bi-partite lattice, one can obtain
an antiferromagnetic insulator already below the Mott transition, i.e., before electrons are essentially localized. This is
indeed found for the square lattice (n = 1), where the Mott
transition is replaced by a smooth crossover from a band
(or "Slater" [19]) insulator with small alternating magnetic
moments at small U to a (Heisenberg) antiferromagnetic
insulator with fully developed local moments at large U.
Interestingly, this is not the case for the honeycomb lattice, where antiferromagnetism sets in essentially together
with the Mott transition [20], although the detailed behavior
close to the transition appears to be more complicated –
and quite intriguing [21].
The problem of evaluating the ground state energy
E 6W@ =
t W
W H
WW
(5)
(4)
for this trial state still represents a formidable task. Exact
results were only obtained in one dimension [9, 10]. For other dimensions, Variational Monte Carlo (VMC), pioneered
for the Gutzwiller ansatz by Horsch and Kaplan [11], has
been widely used in recent years [12].
Gutzwiller himself proposed an approximate way of evaluating Eq. (4) [3]. His procedure, known as "Gutzwiller approximation", involves two steps [13]. In a first step, the
expectation value is factorized with respect to spin. In a
second step, the remaining expectation values are assumed to be configuration-independent. This leads to a
purely combinatorial problem. In the limit of infinite dimensions, the Gutzwiller approximation represents the exact
solution for the Gutzwiller ansatz, as shown by Metzner and
Vollhardt [14, 10]. This interesting result marked the beginning of a new era in the theory of correlated electrons, that
of the Dynamical Mean-Field Theory [15].
As a second example of a broken symmetry we mention
bond alternation in conjugated polymers, or, more precisely, the fate of the Peierls instability in the presence of Coulomb interaction. Eric Jeckelmann, during his Ph.D. thesis,
The result of the Gutzwiller approximation can be represented in terms of a renormalized hopping, t " gt. For U " ∞,
1 From this point on, we will concentrate mostly on our own work, with
apologies to other authors.
38
Communications de la SSP No. 37
studied the one-dimensional Peierls-Hubbard model where
the bond length dependence of the hopping amplitude t
provides a coupling between the electrons and the lattice
[22]. He used the Gutzwiller ansatz but added both the
electronic gap and the lattice dimerization as variational
parameters. The result for the dimerization D, as a function
of U and for fixed electron-lattice couplings , is shown in
Fig. 1. In contrast to Unrestricted Hartree-Fock, where the
Peierls insulator is rapidly replaced by a spin-density wave
(a Slater insulator), the dimerization is found to remain finite
for all values of U. It even increases initially, as discovered
long before this work [23], and exhibits a maximum for U
≈ 4t, where a crossover to spin-Peierls behavior occurs.
These variational results are in good agreement with subsequent calculations using the Density Matrix Renormalization Group.
Figure 2: Superconducting order parameter as a function of doping for the Hubbard model on the square lattice.
0.20
which ferromagnetism occurs if U(eF) > 1, where (eF) is the
density of states per spin at the Fermi energy. Already in
1953 Van Vleck argued that the Stoner theory could not be
the whole story, but that electronic correlations had to be
taken into account. Gutzwiller’s scheme is well suited for
doing that. The results obtained in this way still leave space
for ferromagnetism, but the stability region in parameter
space is strongly reduced as compared to that of Stoner’s
theory [25]. In fact, the necessary U values are so large that
one has to conclude that the single-orbital Hubbard model
is not adequate for describing the ferromagnetism of transition metals.
0.15
Δ /(2t)
λ = 0.2
0.10
0.05
0.00
λ = 0.1
0
2
4
6
8
There is another more fundamental reason why the singleband Hubbard model cannot be taken too seriously for
describing transition metals. These materials are characterized by narrow partly filled 3d-bands located within a
broad s-band and overlapping with even broader p bands,
and therefore it is far from obvious how a one-band model
should be able to describe their magnetic properties. This
problem must have been clear to Gutzwiller, who used the
smart title "Correlation of Electrons in a Narrow s Band" for
one of his papers [3]. Notwithstanding this loophole, a realistic model should add uncorrelated electrons representing
the s-band to the correlated electrons of the d-band. The
Periodic Anderson Model is a first step in this direction, it
admits two orbitals at each site, one of which is localized
and correlated through an on-site interaction, the other is
delocalized and uncorrelated. The two bands are hybridized. Using a generalized Gutzwiller ansatz together with a
corresponding Gutzwiller approximation, one finds not only
the usual renormalization of the correlated band by a factor
g, but also a renormalization of the hybridization by √g [26,
27].
U/t
Figure 1: Dimerization in the Hubbard-Peierls model. Circles:
VMC, full lines: analytical small U expansion, broken lines: Unrestricted Hartree-Fock.
As a third example we discuss results of the Ph. D. thesis of
David Eichenberger [24], who studied the Hubbard model
on a square lattice, using the modified Gutzwiller ansatz
t
t
W = e -hT e -gD W 0
(6)
t
The additional factor e -hT leads to a substantial improvement of the ground state energy and provides a kinetic exchange. We were particularly interested in the possibility
of a superconducting ground state with d-wave symmetry,
taken into account in the reference state W 0 . Fig. 2 shows
the VMC result for the superconducting order parameter
for the Hubbard model on an 8×8 square lattice with both
nearest (t) and next-nearest neighbor hoppings (t') and a
realistic Hubbard parameter U = 8t. Our results agree very
well with other studies using completely different methods.
The next step is to treat two or more correlated orbitals at
a site. Here, Jörg Bünemann in his Ph.D. thesis has contributed a great deal to generalize the Gutzwiller formalism
[28]. The generalization leads to an enormous expansion of
the Gutzwiller wave function, as many additional correlators have to be introduced. The relevant local multi-electron
configurations can be represented by the eigenstates of an
atomic Hamiltonian, which reproduces the atomic multiplet
spectrum of the partly filled 3d shell. This extension also
We turn now to the problem of itinerant ferromagnetism,
which has been the main motivation for Gutzwiller (and
for Hubbard and Kanamori as well) to study the Hamiltonian (1). The most simple trial state is the ground state of
an effective single-particle model where the bands for up
and down spins are shifted relative to each other. The "exchange splitting" is then determined by minimizing the total energy. This leads to the Stoner criterion, according to
39
SPG Mitteilungen Nr. 37
[6] P. W. Anderson, Phys. Rev. 115, 2 (1959).
[7] J. Hubbard, Proc. Roy. Soc. A276, 238 (1963).
[8] J. Kanamori, Prog. Theor. Phys. 30, 275 (1963).
[9] W. Metzner and D. Vollhardt, Phys. Rev. Lett. 59, 121 (1987); F.
Gebhard and D. Vollhardt, Phys. Rev. Lett. 59, 1472 (1987).
[10] For a review see F. Gebhard, The Mott Metal-Insulator Transition: Models and Methods, Springer 1997.
[11] P. Horsch and T. A. Kaplan, J. Phys. C 16, L1203 (1983).
[12] For a recent review of the method for the fully projected Gutzwiller wave function (g " ∞) see B. Edegger, V. N. Muthukumar and
C. Gros, Adv. Phys. 56, 927 (2007).
[13] For a clear presentation see P. Fulde, Electron Correlations
in Molecules and Solids, Springer Series in Solid-State Sciences
100 (1990).
[14] W. Metzner and D. Vollhardt, Phys. Rev. Lett. 62, 324 (1989).
[15] For an early review see A. Georges, G. Kotliar, W. Krauth and
M. J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996).
[16] W. Brinkman and T. M. Rice, Phys. Rev. B 2, 4302 (1970).
[17] W. Kohn, Phys. Rev. 133, A171 (1964).
[18] L. M. Martelo, M. Dzierzawa and D. Baeriswyl, Z. Phys. B 103,
335 (1997).
[19] J. C. Slater, Phys. Rev. 82, 538 (1951).
[20] M. Dzierzawa, D. Baeriswyl and L. M. Martelo, Helv. Phys.
Acta 70, 124 (1997); for a review see D. Baeriswyl, Found. Phys.
30, 2033 (2000).
[21] Z. Y. Meng, T. C. Lang, S. Wessel, F. F. Assaad and A. Muramatsu, Nature 464, 847 (2010).
[22] E. Jeckelmann, Ph D. thesis, University of Fribourg (1995); E.
Jeckelmann and D. Baeriswyl, Synth. Met. 65, 211 (1994).
[23] P. Horsch, Phys. Rev. B 24, 7351 (1981); D. Baeriswyl and K.
Maki, Phys. Rev. B 31, 6633 (1985).
[24] D. Eichenberger, Ph. D. thesis, University of Fribourg (2008);
D. Baeriswyl, D. Eichenberger and M. Menteshashvili, New J.
Phys. 11, 075010 (2009).
[25] P. Fazekas, Electron Correlation and Magnetism, World Scientific 1999.
[26] T. M. Rice and K. Ueda, Phys. Rev. Lett. 55, 995 (1985).
[27] C. M. Varma, W. Weber and L. J. Randall, Phys. Rev. B 33,
1015 (1986).
[28] J. Bünemann, Ph. D. thesis, University of Dortmund (1998);
J. Bünemann, W. Weber and F. Gebhard, Phys. Rev. B 57, 6896
(1998).
[29] For a recent review see O. K. Andersen and L. Boeri, Ann.
Phys. (Berlin) 523, 8 (2011).
[30] J. Bünemann et al., Europhys. Lett. 61, 667 (2003).
[31] J. Bünemann, F. Gebhard, T. Ohm, S. Weiser and W. Weber,
Phys. Rev. Lett. 101, 236404 (2008).
[32] T. Schickling et al., Phys. Rev. Lett. 108, 036406 (2012).
leads to a rapid increase of the number of variational parameters in the Gutzwiller wave function. If the number of
different orbitals is N (N can be as large as 5 for an open
d shell), the number of independent variational parameters
can reach 22N - 2N - 1, which may be of the order of 1000
[28]. The variational parameters represent the occupancies of all possible multiplet states. At the first instance,
the atomic multiplet spectrum is governed by three SlaterCondon or Racah integrals, when spherical symmetry is assumed for the atoms. Yet, the site symmetry in a crystal is
lower than spherical. Incorporation of the correct site symmetry results in many further modifications and extensions
of the method.
The multi-band Gutzwiller method allows the investigation
of 3d transition metals and compounds on a quantitative
basis. An ab initio single-particle Hamiltonian can be constructed using Density-Functional Theory (DFT). The simplest way to incorporate DFT results is to extract a tightbinding model by fitting the hopping amplitudes to the DFT
bands, but more elaborate methods are available, such as
down-folding the DFT bands to a reduced Wannier basis
[29]. We have carried out various studies on magnetic 3d
elements and on compounds of 3d elements. One paper
dealt with the Fermi surface of ferromagnetic Ni. DFT predicts a hole ellipsoid around the X point of the Brillouin
zone, which is missing in the data. The multi-band Gutzwiller method was based on a one-particle Hamiltonian derived from paramagnetic DFT bands for Ni including wide
4s and 4p bands.
Using typical interaction parameters for Ni, our calculations reproduced the observed Fermi surface topology [30].
Another paper dealt with the magnetic anisotropy in ferromagnetic Ni [31]. Here again, pure DFT results did not yield
the correct answers, while the Gutzwiller method gave very
good agreement with experiment. In all cases, the renormalization parameters g have been found to be of the order
of 0.7, indicating moderately strong correlation effects.
Finally we mention the issue of metallic anti-ferromagnetism
in iron pnictides, a new class of high-temperature superconductors. Our calculations were based on down-folded
DFT bands. The results indicate also in this case moderately strong correlations. The atomic magnetic moments were
found to agree well with experiment, in contrast to the DFT
results and also to model calculations [32].
The examples mentioned above demonstrate that Gutzwiller's simple ansatz evolved into a powerful tool for dealing
with correlated electron systems. The method has recently
also been applied successfully to cold bosonic atoms in an
optical lattice. At the age of 50, Gutzwiller’s wave function
in its extensions remains competitive for describing correlated states of matter.
Werner Weber received his PhD from the TU Munich
in 1972. He worked first at a variety of research institutions, at the MPI for Solid State Research in Stuttgart,
at the Research Center in Karlsruhe (now K.I.T.), at
Bell Laboratories, Murray Hill. He then became a faculty member at the TU Dortmund, where he retired in
2010. His research area is theoretical solid state physics, with main emphasis on materials science theory.
He assumed many duties in university self-administration, even presently. In the spirit of Martin Gutzwiller,
he recently changed his field of interest to activities in
climate research, including applications.
References
[1] M. C. Gutzwiller, Phys. Rev. Lett. 10, 169 (1963).
[2] M. C. Gutzwiller, Phys. Rev. 134, A923 (1964).
[3] M. C. Gutzwiller, Phys. Rev. 137, A1726 (1965).
[4] K. A. Chao and M. C. Gutzwiller, J. Appl. Phys. 42, 1420 (1971).
[5] J. H. van Vleck, Rev. Mod. Phys. 25, 220 (1953).
40
Communications de la SSP No. 37
Physik und Gesellschaft
"Lead-User-Workshops" für effizientes
Innovations- & Produktvariantenmanagement
Bernhard Braunecker und Richard Wenk
Industriephysiker in Managementfunktion
Physiker sind in der Industrie nicht nur in Forschung und
Entwicklung tätig, sondern auch als Produktmanager. In
dieser Funktion müssen sie sich um drei Fragen kümmern:
a) wie leistungsstark und erprobt sind die dem Produkt und
dem Herstellprozess zugrunde liegenden Technologien, b)
wie gut deckt das Produkt heutige und zukünftige Kundenanwendungen ab und c) wie wird es sich am Markt behaupten? Um den wirtschaftlichen Erfolg des Produkts zu
sichern, müssen alle drei Fragen kohärent, also im Kontext
positiv beantwortet sein. Die Abhängigkeit der Fragestellungen voneinander spiegelt sich zum Beispiel bei der Festlegung des Produktkonzepts wider: einerseits möchte man
ein entsprechend grosses Angebot an Produktvarianten,
um ein möglichst breites Kundenspektrum abzudecken;
anderseits erfordern die für den Markterfolg zu minimierenden Herstell- und Vertriebskosten die Beschränkung auf
nur wenige Varianten. Selbst wenn man den Widerspruch
dadurch löst, dass man die Produkte baukastenmässig aus
Modulen aufbaut, bleibt dennoch die Frage b) zu beantworten, ob sich damit auch alle gewünschten Kundenapplikationen erfüllen lassen?
Alpha-Beziehungen von Physikern zwischen Firmen
Unter diesem Begriff sei verstanden, wenn die Geschäftsbeziehung zweier Firmen über das übliche Kunden/Lieferantenverhältnis hinausgeht, wenn also beider Primär­
interessen strategisch in die gleiche Richtung zielen. Als
klassisches Beispiel gilt das in der Optikindustrie enge
Verhältnis zu den Glasherstellern, deren beste Lieferqualität gerade gut genug ist für hochwertige Optiksysteme.
Besonders wichtig war und ist der Kontakt zwischen den
Optikentwicklern im deutschsprachigen Raum und den
Glasexperten von Schott in Mainz, um die hohen Qualitätsansprüche ans Glas, aber auch die Komplexität der Glasproduktion jeweils der anderen Seite verständlich zu machen. Dazu organisiert Schott seit Jahrzehnten regelmässig
sogenannte "Designer"-Treffen, zu denen die gesamte Optikindustrie ihre Wissenschaftler schickt, um Probleme und
Anregungen zu artikulieren.
Als Folge dieser Treffen bildete sich unter den Optikentwicklern eine Gemeinschaft über Firmengrenzen hinaus
und bei vielen Kollegen zusätzlich auch ein enges Verhältnis zu den Glasproduktionsleuten, das sich zur Lösung von
Problemfällen in der täglichen Praxis als vorteilhaft erweist.
Als vor einigen Jahren japanische Glasherstellern überraschend "bleifreie" Gläser am Markt lancierten, konnte
Schott unter Mithilfe der Experten aller grosser Optikfirmen
im deutschsprachigen Raum rasch und gezielt auf die neue
Situation reagieren. Diese "Alpha-Beziehungen" sind daher
für beide Seiten ein wirksames Mittel der Risikominimierung (risk mitigation), sowohl in technischen Belangen, wie
in der strategischen Ausrichtung.
Man sieht, dass die drei Fragestellungen ein profundes
Verständnis der technisch-kommerziellen Abhängigkeiten
erfordern, besonders, wenn neue Technologien ins Spiel
gelangen. Während die Marktaspekte von Marketingleuten
abgedeckt werden können, muss die Schnittstelle der Applikationen gemeinsam von Marketing und F&E bearbeitet
werden. Sollte sich das angesprochene Modularkonzept
dann als geeignet und machbar erweisen, ist es Aufgabe
der F&E - Wissenschaftler, die Funktionalität und die Struktur der Module festzulegen. Nur wie lässt sich in diesem
iterativen und mit vielen Fragezeichen versehenen Prozess
mehr Gewissheit über das richtige Vorgehen gewinnen?
Konzept eines "Lead-User-Workshops"
Im Folgenden wird die Vorgehensweise beschrieben, wie
vor einigen Jahren bei Leica Geosystems in Heerbrugg ein
Lead-User-Workshop zum anstehenden Thema der Digitalisierung von Vermessungsgeräten organisiert wurde. Dazu
wurden 15 Experten aus aller Welt aus den Bereichen der
amtlichen Landesvermessung, der Industrie, dem Bauwesen und der Denkmalpflege (cultural heritage) eingeladen.
Das Ziel war, internes Technologie-Knowhow mit dem Applikations-Knowhow der externen Experten zu kombinieren. Im Vorfeld des WS wurden verschiedene, für Leica interessante Applikationsfelder (total 6) definiert, die dann am
WS vorgestellt und bearbeitet werden sollten. Dabei sollten
die externen Experten nach Kenntnis der neuen Technologieansätze sich nicht nur mit den möglichen Folgen für
ihr eigenes Arbeitsgebiet auseinandersetzen, sondern auch
mit dem ihrer Kollegen. Das sollte wichtige Argumente für
die erwähnte Modularisierung liefern.
Ein sehr leistungsstarkes Werkzeug dazu sind sogenannte
Lead-User-Workshops, wo man als Produkthersteller mit
Repräsentanten wichtiger Kunden gemeinsam herauszufinden versucht, welche neuen Anwendungen durch den Einsatz kommender Technologien denkbar wären, und welche
Produktvarianten dazu infrage kämen? Der Meinungsaustausch geschieht im gegenseitigen Interesse, da danach
beide Seiten die Folgen anstehender Entscheide besser
einzuschätzen vermögen. Bevor im Folgenden auf die Gestaltung eines solchen Workshops eingegangen wird, sei
am Beispiel der Optikindustrie illustriert, dass Veranstaltungen dieser Art zur Bildung von auch in Krisensituationen
belastbaren Interessengemeinschaften (Communities) führen können.
41
SPG Mitteilungen Nr. 37
Auswahl der externen Teilnehmer
Die Auswahl der Experten ist die wichtigste Aufgabe, die
von den Marketing- und Vertriebsleuten, gemeinsam mit
den Auslandsvertretern, vorgenommen werden muss. Als
Kriterien gelten, dass zu den Personen ein langjähriges
Vertrauensverhältnis besteht, dass sie als Entscheidungsträger mit technischem Hintergrund noch Kenntnis der Abläufe in der täglichen Praxis haben, und dass sie offen für
Neues sind.
•In unserem Falle waren die Experten in folgenden Organisationen tätig:
a) Fünf Ingenieurbüros und KMUs mit Fokus auf Architektur, Katastervermessung, Hoch-/Tiefbau, Tunnelbau,
b) fünf Institutionen (Universitäten, Behörden, Ämter für
Denkmalpflege), und c) fünf "Big players" (Shell Oil, British Rail, CERN & US-Freeway companies).
•Sie kamen aus vier Regionen, logarithmisch gewichtet:
a) Schweiz, b) Deutschland / Österreich, c) Europa, d)
USA,
•Und sie deckten folgende Applikationsfelder ab:
a) Traditionelle Märkte, b) Nischenmärkte mit Wachstumspotential, c) Neue Märkte.
Gruppeneinteilung
Es wurden drei Arbeitsgruppen mit jeweils fünf externen
Experten gebildet, wobei in jeder Gruppe alle vier Regionen vertreten waren. Jeder Gruppe wird zugeteilt ein Moderator, sowie ein Produktmanager aus Marketing und ein
technischer Berater aus F&E, die nur bei Klärungsbedarf
eingreifen sollten.
Ablauf der Veranstaltung
Die Teilnehmer in den 3 Gruppen mussten jeweils zwei der
Applikationsfelder wie folgt bearbeiten:
Schritt 1: Erarbeiten von speziellen Messabläufen (User
Workflow) in den definierten Applikationsfeldern.
Schritt 2: Identifizieren von Problemen und deren Lösung,
um den Messablauf wesentlich zu vereinfachen und zu verkürzen.
Schritt 3: Identifizieren von Kundenanforderungen für zukünftige Messsysteme.
Schritt 4: Erarbeiten von Konzeptvorschlägen für zukünftige Messsysteme.
Der Workshop (Figur 1) wurde dreiteilig angelegt:
•Im Teil 1 schilderte jeder Teilnehmer typische Abläufe
seiner täglichen Arbeit und verwies auf Probleme und
Verbesserungswünsche (Schritte 1 & 2). Damit gewann
jedes Gruppenmitglied Kenntnis über die Tätigkeiten
der Anderen. Nach der Gruppenarbeit präsentierte der
Moderator im Plenum vor allen Teilnehmern erste Gemeinsamkeiten in der noch sehr heterogenen Analyse
und skizzierte erste Verbesserungswünsche.
•Im Teil 2 informierte der F&E-Leiter der einladenden
Firma, welche neuen Technologien in nächster Zeit zu
erwarten sind. Dieser Schritt ist der psychologisch wichtige Icebreaker, der im geschilderten Fall auch zu einer
spürbaren Solidarisierung der Experten untereinander
und mit dem Veranstalter führte.
•Im Teil 3 wurden in neuer Zusammensetzung der Gruppen die Konzeptvorschläge für zukünftige Messsysteme
(Schritte 3 & 4) diskutiert, nun allerdings im Wissen kommender Technologiemöglichkeiten. Da die Grundaufgaben aller Teilnehmer meist ähnlicher Natur waren, war
die Diskussion in allen Gruppen deutlich einheitlicher als
am ersten Tag. Die darauf vorbereiteten Moderatoren
lenkten deshalb die Diskussion in Richtung allgemein
einsetzbarer Hardware- und Softwaremodule. Nach
erneuter Präsentation der Gruppenarbeiten im Plenum
gab der Vertreter des Veranstalters dann eine erste Zusammenfassung der Erkenntnisse (Wrap up).
Ergebnis, Auswertung, weitere Schritte
Nach Ablauf des WS wurden die gesammelten Kundenanregungen für verschiedene Applikationen in den predefinierten Anwendungsfeldern in drei Bereiche unterteilt:
generelle Anwender-, Technologie- und Produktanforderungen. In jedem Bereich wurden die Empfehlungen dann
konsolidiert, also möglichst vereinheitlicht über alle Anwen-
Figur 1: Teilnehmer eines Lead User Workshops
bei Leica Geosystems
42
Communications de la SSP No. 37
dungsfelder hinweg. So konnte man bei den generellen Anwenderanforderungen vier Untergruppen bilden, für Genauigkeitssteigerungen, höhere Effizienz des Messsystems,
geringere Störanfälligkeit und mehr Bedienerfreundlichkeit;
im Bereich der Technologie gab es neun Untergruppen wie
Empfehlungen für Echtzeit-Systeme und vereinheitlichtes
Datenformat und im Bereich der Produktanforderungen
sieben Untergruppen, wie z.B. für handhaltbare statt stativmontierte Instrumente, Multisensor Systeme, etc.
Wie einleitend angedeutet, soll ein breites Angebot an Produktvarianten möglichst viele Kundenapplikationen abdecken, demzufolge sich aus Logistik- und Kostengründen
ein modular hierarchischer Aufbau (Figur 2) empfiehlt: Teure
Basismodule wie Optik, Mechanik und Elektronik werden
standardisiert, also konstruktiv vereinheitlicht, während die
Produktdifferenzierung möglichst weit ans Ende der Wertschöpfungskette geschoben wird, im Idealfall sogar in reine Softwaremodule. Im Gegensatz zu früher kann deshalb
auch die kostengünstigste Variante die beste Hardware
enthalten, wenn es sich wegen der grösseren Stückzahl
und der Fertigungsautomatisierung lohnt. Die eigentliche
Kernfrage lautet deshalb, mittels welcher Modulfunktionen
kann Redundanz reduziert und die angestrebte Vollständigkeit des Applikationsspektrum realisiert werden? Bei der
Beantwortung dieser Frage helfen die wichtigen Erkenntnisse aus dem Lead User Workshop.
Aus diesen Anforderungskatalogen wurden dann Funktionen für die verschiedenen Produktgruppen abgeleitet.
Grundsätzlich wurde dabei unterschieden zwischen Produktverbesserungen, also Optionen für die unmittelbare
Zukunft, Innovationen, die interne F&E Anstrengungen
benötigen, und Visionen, also Konzepte für zukünftige Systeme, die eine Grundlagenentwicklung mit Hochschulpartnern bedingen. Daraus wurden dann konkrete Produktideen abgeleitet, woraus letztendlich für die verschiedenen
Produktkategorien 17 Produktvorschläge resultierten.
Diese Produktideen flossen dann bei den entsprechenden
Divisionen in deren Roadmap-Prozess ein, wurden von
den Produkt- und Technologiespezialisten dort hinterfragt, und es wurden realistische Produktentwicklungen
definiert. Einige dieser Ideen konnten noch in bereits laufende Produktentwicklungen eingebracht werden, andere wurden verworfen aus Gründen der Machbarkeit oder
weil der Bedarf aus Kundensicht noch nicht gegeben war,
wieder andere wurden zurückgestellt, beziehungsweise als
Kandidaten für externe Entwicklungen mit Hochschulen
vorgesehen. Dabei wurde verstärktes Augenwerk auf eine
mögliche Modularisierung gerichtet, also auf die Mehrfachverwendung von Grundmodulen (Principal Components) in
verschiedenen Instrumenten und Dienstleistungen.
Figur 2: Produktvarianten P1…P5: Die Hardwareplattformen Optik
& Mechanik sind konzeptionell zu vereinheitlichen und an einem
Standort vollautomatisch herzustellen. Der Einbau der "intermediate" Module von Elektronik & Sensorik kann weltweit an mehreren
Standorten durchgeführt werden, während die applikationsspezifischen Software-Module im Idealfall vom Kunden selber freigeschaltet werden können.
Richard Wenk ist CTO und Vizepräsident bei Hexagon
Geosystems, zu der auch Leica Geosystems in Heerbrugg gehört.
Optimales Konzept des Variantenmanagements
Die gewonnenen Erkenntnisse aus einem Lead-User-Workshop fliessen in die Auslegung zukünftiger Instrumente ein.
History of Physics (4)
From Static to Expanding Models of the Universe
Norbert Straumann, Uni Zürich
Einstein's static model of the universe
At the end of some historical remarks in the article on the
2011 Nobel Prize [1], it was announced that the author
would indicate in a historical essay the interesting early history of cosmology. One of the reasons is that this is not
even well-known among cosmologists, and is often distorted. In the words of the late Allen Sandage: "In 1929, Edwin
Hubble published a paper that correlated redshifts of galaxies with distances he had estimated from calibration of their
absolute magnitudes previously made in 1926. Writers of
both popular accounts and technical textbooks have often
described this as the discovery of the expanding universe.
This is not so." [2]
On 8 February 1917, in the middle of the most terrible time
during the First World War, Einstein gave a talk in the Preussian Academy of Sciences on an application of his general
relativity on the universe as a whole. One week before the
German military leadership had declared in the same city
the unconstrained submarine war. Einstein’s first paper on
cosmology [3] marks in many ways the beginning of modern cosmology.
Perhaps the main reason why Einstein turned so soon after the completion of general relativity to cosmology had
much to do with Machian ideas on the origin of inertia,
43
SPG Mitteilungen Nr. 37
itation. It has to be emphasized, however, that a positive
curvature of space is given by our results, even if the supplementary term is not introduced. That term is necessary
only for the purpose of making possible a quasi-static distribution of matter, as required by the fact of the small velocities of the stars."
which played in those years an important role in Einstein’s
thinking. His intention was to eliminate all vestiges of absolute space. He was, in particular, convinced that isolated
masses cannot impose a structure on space at infinity. Einstein was actually thinking about the problem regarding the
choice of boundary conditions at infinity already in spring
1916. In a letter to Michele Besso from 14 May 1916 he
also mentions the possibility of the world being finite. A few
months later he expanded on this in letters to Willem de
Sitter. It is along these lines that he postulated a Universe
that is spatially finite and closed, a Universe in which no
boundary conditions are needed 1. He then believed that
this was the only way to satisfy what he later [5] named
Mach’s principle, in the sense that the metric field should
be determined uniquely by the energy-momentum tensor.
In addition, Einstein assumed that the Universe was static.
This was not unreasonable at the time, because the relative velocities of the stars as
observed were small. (Recall that astronomers only
learned later that spiral nebulae are independent star
systems outside the Milky
Way. This was definitely
established when in 1924
Hubble found that there
were Cepheid variables in
Andromeda and also in other nearby galaxies. Einstein
compares the observed
small peculiar velocities of
stars with the speed of light.)
Edwin Hubble
These two assumptions
were, however, not compatible with Einstein’s original field
equations. For this reason, Einstein added the famous Lterm, which is compatible with the principles of general
relativity. The cosmological term is, in four dimensions, the
only possible complication of the field equations if no higher than second order derivatives of the metric are allowed
(Lovelock theorem). This remarkable uniqueness is one of
the most attractive features of general relativity. (In higher
dimensions additional terms satisfying this requirement are
allowed.)
For the static Einstein universe the field equations with the
cosmological term imply the two relations
To de Sitter he emphasized in a letter on 12 March 1917,
that his cosmological model was intended primarily to settle the question "whether the basic idea of relativity can be
followed through its completion, or whether it leads to contradictions". And he adds whether the model corresponds
to reality was another matter.
Only later Einstein came to realize that Mach's philosophy
is predicated on an antiquated ontology that seeks to reduce the metric field to an epiphenomenon of matter. It
became increasingly clear to him that the metric field has
an independent existence, and his enthusiasm for what he
called Mach's principle later decreased. In a letter to F. Pirani he wrote in 1954: "As a matter of fact, one should no
longer speak of Mach's principle at all." GR still preserves
some remnant of Newton’s absolute space and time.
De Sitter model
Surprisingly to Einstein, de Sitter discovered in the same
year, 1917, a completely different static cosmological model which also incorporated the cosmological constant, but
was anti-Machian, because it contained no matter [6]. For
this reason, Einstein tried to discard it on various grounds
(more on this below). The original form of the metric was:
dr 2
g = - 81 - ( r ) 2B dt 2 +
+ r 2 ^dj + sin 2 jd{ 2 h .
R
1 - ( r )2
R
Here, the spatial part is the standard metric of a threesphere of radius R, with R = (3/L)1/2. The model had one
very interesting property: For light sources moving along
static world lines there is a gravitational redshift, which
became known as the de Sitter effect. This was thought
to have some bearing on the redshift results obtained by
Slipher. Because the fundamental (static) worldlines in this
model are not geodesic, a freely-falling object released by
any static observer will be seen by him to accelerate away,
generating also local velocity (Doppler) redshifts corresponding to peculiar velocities. In the second edition of his
book [7], published in 1924, Eddington writes about this:
"de Sitter's theory gives a double explanation for this motion of recession; first there is a general tendency to scatter (...); second there is a general displacement of spectral
lines to the red in distant objects owing to the slowing down
of atomic vibrations (...), which would erroneously be interpreted as a motion of recession."
I do not want to enter into all the confusion over the de Sitter
universe. One source of this was the apparent singularity at
r = R = (3/L)1/2. This was at first thoroughly misunderstood
even by Einstein and Weyl. ("The Einstein-de Sitter-WeylKlein Debate" is now published in Vol. 8 of the Collected
Papers [4].) At the end, Einstein had to acknowledge that
de Sitter's solution is fully regular and matter-free and thus
indeed a counter example to Mach's principle. But he still
discarded the solution as physically irrelevant because it
is not globally static. This is clearly expressed in a letter
4rGt = 12 = K ,
a
where r is the mass density of the dust filled universe (zero
pressure) and a is the radius of curvature. For L = 0 the
density r would have to vanish. (We remark, in passing, that
the Einstein universe is the only static dust solution; one
does not have to assume isotropy or homogeneity.) Einstein was very pleased by this direct connection between
the mass density and geometry, because he thought that
this was in accord with Mach's philosophy.
Einstein concludes with the following sentences:
"In order to arrive at this consistent view, we admittedly had
to introduce an extension of the field equations of gravitation which is not justified by our actual knowledge of grav1 The spatial geometry in Einstein's model is that of a three-sphere, i.e.,
the surface of a sphere in four-dimensional Euclidean space. This is a
prototype of a highly symmetric compact manifold without boundary.
44
Communications de la SSP No. 37
from Weyl to Klein, after he had discussed the issue during
a visit of Einstein in Zürich [8]. An important discussion of
the redshift of galaxies in de Sitter's model by H. Weyl in
1923 should be mentioned. Weyl introduced an expanding
version 2 of the de Sitter model [9]. For small distances his
result reduced to what later became known as the Hubble
law. Independently of Weyl, Cornelius Lanczos introduced
in 1922 also a non-stationary interpretation of de Sitter's
solution in the form of a Friedmann spacetime with a positive spatial curvature [10]. In a second paper he also derived the redshift for the non-stationary interpretation [11].
for small distances to a linear relation, known as Hubble's
law. He also estimated the Hubble constant H0 based on
Slipher's redshift data for about 40 nebulae, and Hubble's
1925 distance determination to Andromeda, as well as the
the magnitudes of nebulae published by him in 1926. Two
years before Hubble he found a value only somewhat higher than the one Hubble obtained in 1929. (Actually, Lemaître
gave two values for H0.) But this seminal work was almost
completely ignored. The general attitude is well illustrated
by the following remark of Eddington at a Royal Society
meeting in January, 1930: "One puzzling question is why
there should be only two solutions. I suppose the trouble is
that people look for static solutions."
Lemaître, who had been for a short time a post-doctoral
student of Eddington, read this remark in a report on the
meeting published in Observatory, and wrote to Eddington
pointing out his 1927 paper. Eddington had seen that paper, but had completely forgotten about it. But now he was
greatly impressed and recommended Lemaître's work in a
letter to Nature. He also arranged for a translation which
appeared in MNRAS [13]. Eddington also "pointed out that
it was immediately deducible from his [Lemaître's] formulae
that Einstein's world is unstable, so that an expanding or a
contracting universe is an inevitable result of Einstein's law
of gravitation."
Lemaître's successful explanation of Hubble's improved
data, carefully analysed by de Sitter in a series of papers,
finally changed the viewpoint of the majority of workers in
the field. At this point, after a stay with Eddington, and a visit
to the Mount Wilson Observatory, Einstein rejected the cosmological term as superfluous and no longer justified [14].
At the end of the paper in which he published his new view,
From static to expanding world models
Until about 1930 almost
everybody believed that the
Universe was static, in spite
of the two fundamental papers by Friedmann [12] in
1922 and 1924 and Lemaître's independent work [13]
in 1927. These path breaking papers were in fact
largely ignored. The history
of this early period has - as
is often the case - been distorted by some widely read
Alexander Friedmann
documents. Einstein too
accepted the idea of an expanding Universe only much later. After the first paper of
Friedmann, he published a brief note claiming an error in
Friedmann's work; when it was pointed out to him that it
was his error, Einstein published a retraction of his comment, with a sentence that luckily was deleted before publication: "[Friedmann's paper] while mathematically correct
is of no physical significance". In comments to Lemaître
during the Solvay meeting in 1927, Einstein again rejected
the expanding universe solutions as physically unacceptable. According to Lemaître, Einstein was telling him: "Vos
calculs sont corrects, mais votre physique est abominable".
It appears astonishing that Einstein - after having studied
carefully Friedmann's papers - did not realize that his static
model is unstable, and hence that the Universe has to be
expanding or contracting. On the other hand, I found in the
archive of the ETH many years ago a postcard of Einstein
to Weyl from 1923, related to Weyl's reinterpretation of de
Sitter's solution, with the following interesting sentence: "If
there is no quasi-static world, then away with the cosmological term".
It also is not well-known that Hubble interpreted in 1929
the redshifts of radiation emitted by distant 'nebulae' in the
framework of the de Sitter model, as had been suggested
by Eddington.
Lemaître discovers the expanding universe
We repeat what we said in [1] about Lemaître's key role
in the founding period of cosmology. He was the first person who seriously proposed an expanding universe as a
model of the real universe. He derived in his crucial paper of
1927 the general redshift formula, and showed that it leads
2 The de Sitter model has many different interpretations, depending on
the choice of the velocity field for the subdominant matter flow.
Letter from Lemaître to Eddington
45
SPG Mitteilungen Nr. 37
L-force is not important, the expansion is decelerated due
to gravity and slowly approaches the radius of the Einstein
universe. At about the same time, the repulsion becomes
stronger than gravity and a second stage of expansion begins which eventually inflates. In this way a positive L was
employed to reconcile the expansion of the Universe with
the age of stars.
Lemaître was also the first who associated in 1933 the
cosmological constant with vacuum energy. Actually, Pauli
made before the advent of the new quantum mechanics
some simple, but profound remarks on this issue [15].
To a minority of cosmologists who had read the French
original of Lemaître's 1927 paper, it was known that a few
paragraphs were deleted in the translation, notably the one
in which Lemaître assessed the evidence for linearity of the
distance-velocity relation and estimated the expansion rate.
Fortunately, the origin of this curious fact has very recently
been completely cleared up [16]. It was Lemaître himself
who translated his original paper. The correspondence of
him with the editor of MNRAS, quoted in [16], shows that
Lemaître was not very interested in establishing priority. He
saw no point in repeating in 1931 his findings four years
earlier, since the quality of the observational data had in the
meantime been improved. This is one of the reasons that
Hubble was elevated to the discoverer of the expanding
universe.
For much more on all this I refer again to the recent excellent book [17] of our Swiss colleagues Harry Nussbaumer
and Lydia Bieri.
References
Albert Einstein and Georges Lemaître
Einstein adds some remarks about the age problem which
was quite severe without the L-term, since Hubble's value
of the Hubble parameter was then about seven times too
large. Einstein is, however, not very worried and suggests
two ways out. First he says that the matter distribution is
in reality inhomogeneous and that the approximate treatment may be illusionary. Then he adds that in astronomy
one should be cautious with large extrapolations in time.
After the L-force was rejected by its inventor, other cosmologists, such as Eddington and Lemaître, retained it. One
major reason was that it solved the problem of the age of
the Universe when the Hubble time scale was thought to
be only 2 billion years (corresponding to the value H0 ~ 500
km s-1 Mpc-1 of the Hubble constant). This was even shorter
than the age of the Earth. In addition, Eddington and others
overestimated the age of stars and stellar systems.
For this reason, the L-term was employed again and a
model was revived which Lemaître had singled out from the
many solutions of the Friedmann-Lemaître equations 3. This
so-called Lemaître hesitation universe is closed and has a
repulsive L-force (L > 0), which is slightly greater than the
value chosen by Einstein. It begins with a big bang and
has the following two stages of expansion. In the first the
[1] N. Straumann, The 2011 Nobel Prize in Physics, SPG Mitteilungen, Nr. 36, Januar 2012.
[2] A. Sandage, Preface to [17].
[3] A. Einstein, Sitzungsber. Preuss. Akad. Wiss. phys.-math. Klasse VI, 142 (1917). See also: [4], Vol. 6, p. 540, Doc. 43.
[4] A. Einstein, The Collected Papers of Albert Einstein, Vols. 1-12,
Princeton University Press, 1987–. See also: [http://www. einstein.
caltech.edu/].
[5] A. Einstein, On the Foundations of the General Theory of Relativity. Ref. [4], Vol. 7, Doc. 4.
[6] W. de Sitter, Proc. Acad. Sci., 19, 1217 (1917); and 20, 229
(1917).
[7] A. S. Eddington, The Mathematical Theory of Relativity. Chelsea Publishing Company (1924). Third (unaltered) Edition (1975).
See especially Sect.70.
[8] Letter from Hermann Weyl to Felix Klein, 7 February 1919; see
also Ref. [5], Vol. 8, Part B, Doc. 567.
[9] H. Weyl, Phys. Zeits. 24, 230, (1923); Phil. Mag. 9, 923 (1930).
[10] C. Lanczos, Phys. Zeits. 23, 539 (1922).
[11] C. Lanczos, Zeits. f. Physik 17, 168 (1923).
[12] A. Friedmann, Z.Phys. 10, 377 (1922); 21, 326 (1924).
[13] G. Lemaître, L’univers en expansion. Ann. Soc. Sci. de Bruxelles 47, 49 (1927). Translated in MNRAS 91, 483 (1931).
[14] A. Einstein, S. B. Preuss. Akad. Wiss. (1931), 235.
[15] N. Straumann, Wolfgang Pauli and Modern Physics, Space
Science Reviews 148, 25 (2009).
[16] M. Livio, Nature 479, 208-211 (2011).
[17] H. Nussbaumer and L. Bieri, Discovering the Expanding Universe, Cambridge University Press (2009).
3 I recall that Friedmann included the L-term in his basic equations. I find
it remarkable that for the negatively curved solutions he pointed out that
these may be open or compact (but not simply connected).
46
Communications de la SSP No. 37
Über den Einfluss des Lichtes auf den Menschen
Mit den beiden folgenden Artikeln dringen wir in das Gebiet der Biophysik ein. Was liegt näher im Jahrhundert des Photons, als den Einfluss des Lichtes auf das menschliche Verhalten zu beschreiben? Vieles, was bislang nur empirisch erfasst
werden konnte, kann heutzutage als Abfolge physikalisch/chemischer Zeitprozesse quantitativ erklärt und modelliert werden. Für die Beleuchtungsindustrie öffnet sich ein riesiges Aktionsfeld, um die Wirkung des Lichtes auf das Wohlbefinden
des Menschen technisch umzusetzen.
Nicht-visuelle Lichtwirkungen beim Menschen
Christian Cajochen, Zentrum für Chronobiologie, Universität Basel
1. Licht eicht die innere Uhr.
Die Tagesrhythmik (Circadianrhythmik) ist eine Spontanrhythmik, die eigentlich in jeder Körperzelle tickt, aber von
einem reiskorngrossen Hirngebiet, das ca. 2 cm hinter
der Nasenwurzel liegt, kontrolliert wird. Dieses Hirngebiet
liegt in den sogenannten suprachiasmatischen Kernen
und umfasst ungefähr 10 bis 20000 Nervenzellen, die als
Schrittmacher fungieren, indem sie eine endogene Spontanaktivität mit einer Rhythmik von 24 Stunden generieren
(Abbildung 1). Falls kein Licht vorhanden ist, oder Dauerlicht herrscht, misst man bei Menschen eine Spontanrhythmik, die im Durchschnitt etwas länger als 24 Stunden, nämlich 24.2 Stunden beträgt. Die Periodenlänge ist individuell
verschieden und zum Teil genetisch determiniert. So haben
Frühtypen (Lerchen) eher kürzere als 24 Stunden Periodenlängen, während Abendtypen (Eulen) eher langsamer >
24.8 Stunden ticken. Leben Menschen unter DauerdunkelLicht- mehr als nur fürs Sehen
heit (z.B. Sehbehinderte) oder Dauerlicht, laufen die TagesLichtwirkungen, die nicht unmittelbar mit dem Sehen zu- rhythmen frei- gemäss der endogenen Periodik (Abbildung
sammenhängen, werden als sogenannte nicht-visuelle 1 oberes Beispiel). Das heisst, die Rhythmen sind nicht
Lichtwirkungen bezeichnet, welche folgend zusammenge- auf den Tag-Nachtwechsel abgestimmt. Der immer wiederkehrende Licht-Dunkelwechsel, dem wir normalerweifasst sind.
se täglich ausgesetzt sind, gleicht diese Spontanrhythmik
auf die exakte 24-Stunden Periodik
der Erdrotation ab (Abbildung 1 unteres Beispiel). Licht wirkt deshalb
als Zeitgeber. Zuwenig Licht für einige Zeit, oder Licht zur falschen
Zeit (z.B. bei der Schichtarbeit),
bringt die innere Uhr aus dem Lot
mit dem natürlichen 24-StundenLicht-Dunkelwechsel, was zu circadianen Schlafstörungen führt. Das
geschieht sehr oft bei Leuten mit
Sehbehinderungen, bei Schichtarbeitern oder wenn man nach dem
Überfliegen von mehreren ZeitzoAbbildung 1. Die Eichung der inneren Uhr durch Licht. Die endogene Circadianrhythmik wird nen mit einem "Jetlag" zu kämpfen
in den suprachiasmatischen Kernen (SCN), einem Hirngebiet im vorderen Hypothalamus, ge- hat. Folgen einer dauernden circadineriert. Das Signal wird über den paraventrikulären Nukleus (PVN), über das superiore Zervi- anen Desynchronisation sind neben
kalganglion im Rückenmark (SCG) zur Pinealis, dem Ort der Melatoninproduktion weitergelei- Schlafstörungen auch gastrointestitet. Die Sekretion des Hormons Melatonin ist tagesrhythmisch unter der Kontrolle der SCN. nale Beschwerden, Depressionen
Falls Dauerlicht oder Dauerdunkelheit aufs Auge fällt, ist der Tagesgang des Melatonins nicht und kardiovaskuläre Störungen. Dosynchronisiert und läuft „frei“, gemäss der endogenen Circadianperiodik, die von 24 Stunsis Wirkungsstudien haben ergeben,
den abweicht (oberes Beispiel). In diesem Beispiel verzögert sich die Melatoninproduktion
dass beim Menschen Lichtstärken
jeden Tag um ca. 0.8 Stunden, weil die endogene Tagesperiodik 24.8 Stunden beträgt. Falls
der periodische Licht-Dunkelwechsel, der durch die Erdrotation genau 24 Stunden beträgt, ab ca. 100 lux wirksam sind für die
wahrgenommen wird, wird dieses Signal vom Auge, über die Netzhaut, via den retinohypo- Eichung der inneren Uhr (Abbildung
thalamischen Trakt (RHT) direkt zu den SCN weitergeleitet. Dieser Licht-Dunkelwechsel wirkt 2). Mit Morgenlicht verschiebt man
als Zeitgeber, das heisst die Endogenperiodik wird auf die Exogenperiodik des 24-Stunden die innere Uhr nach vorne, also in
Lichtdunkelwechsel abgeglichen, man spricht von circadianem „Entrainment“.
eine östliche Zeitzone, während
Ohne sichtbares Licht ist bewusstes Sehen für den Menschen unmöglich. Einfallendes Licht wird in den Augen gesammelt und weiterverarbeitet, damit ein Abbild der Umgebungswelt in unserem Gehirn entsteht. Die Netzhaut im
Auge wandelt die eintreffenden Lichtimpulse in Nervensignale um und leitet sie über den Sehnerv ans Gehirn weiter. Neben den Hirngebieten, die verantwortlich fürs Sehen
sind, trifft die Lichtinformation auch auf Hirnregionen, die
eine wichtige Rolle für die Regulierung circadianer (circa
diem = ungefähr ein Tag) Rhythmen und der Verarbeitung
von Gedächtnisinhalten und Emotionen spielen. Licht spielt
somit eine zentrale "nicht-visuelle" Rolle, die zur Zeit intensiv auf dem Gebiet der Chronobiologie, der Schlafforschung, der Kognitionsforschung, aber zunehmend auch
von Lichtplanern und Architekten erforscht wird.
47
SPG Mitteilungen Nr. 37
Computerbildschirm besser lösten, als wenn sie die gleiche Aufgabe vor einem "normalen" Computerbildschirm
ohne LEDs der gleichen Lichtstärke meistern mussten (Abbildung 3). Neben dem Gedächtnis für deklaratives Lernen
werden auch sogenannt höhere kognitive Funktionen im
Bereich der Exekutivkontrolle und der Daueraufmerksamkeit mit blauangereichertem Licht im Vergleich zu Glühlampenlicht verbessert.
Abbildung 2. Dosis-Wirkungsbeziehung zwischen der Beleuchtungsstärke und der phasenverschiebenden
Wirkung
von Licht nach Zeitzer 1999.
Jedes Quadrat symbolisiert eine
Versuchsperson, die während
6.5 Stunden mit je einer unterschiedlichen Lichtstärke (210000 lux) bestrahlt wurde.
4. Licht wirkt antidepressiv.
Die Lichttherapie ist das Mittel erster Wahl bei der Behandlung von Winterdepressionen, und deren Kosten werden
schon seit über 20 Jahren von den Schweizerischen Krankenkassen vergütet. Zudem zeigen neue Studien, dass
Licht auch bei anderen psychiatrischen Erkrankungen antidepressiv und gegen die häufige Tagesmüdigkeit wirkt.
Hier ist der Wirkungsmechanismus weitgehend unbekannt.
Neuere Untersuchungen mit bildgebenden Verfahren für die
Hirnaktivitätsmessung zeigen, dass Licht direkt auf die sogenannten Mandelkerne wirkt. Das ist ein wichtiges Hirngebiet für die Verarbeitung von Gefühlen und Emotionen.
Licht am Abend die innere Uhr zurückverschiebt in eine
westliche Zeitzone. Mit einem einzigen Lichtpuls von 10000
lux für 3 Stunden kann man die Circadianrhythmik bis zu 2
Stunden vor- bzw. nachverschieben.
2. Licht macht wach.
Eine tagaktive Spezies wie der Mensch empfindet das
Licht als "Wachstimulus". Im Gegensatz dazu wirkt Licht
bei nachtaktiven Tieren schlafinduzierend. Ab etwa 100
lux wirkt Licht bei jungen Menschen wachheitssteigernd.
Das entspricht einer nicht allzu starken Raumbeleuchtung.
Diese Helligkeit kann aber schon vor einem Computerbildschirm sitzend erreicht werden. Neben der Lichtstärke spielt auch die Wellenlänge, also die farbliche Zusammensetzung des Lichts, eine wichtige Rolle. So hat Licht
mit hohen Blauanteilen eine stärkere wachheitssteigernde
Wirkung als Licht in anderen Farben, weil spezielle Lichtrezeptoren in der Netzhaut besonders bei Blaulicht aktiv
werden, und so die nicht-visuellen Lichtwirkungen gezielt
auf das Gehirn weitervermitteln. Es wird vermutet, dass die
Rezeptoren für die nicht-visuellen Lichtwirkungen eng mit
den klassischen visuellen Rezeptoren, den Stäbchen und
Zäpfchen, kommunizieren. Je nach Lichtstärke und Dauer des Lichtstimulus beteiligen sich Stäbchen, Zäpfchen
oder sogenannte "intrinsisch photosensitive Ganglienzellen
in der Netzhaut" unterschiedlich stark an der Vermittlung
nicht-visueller Lichtwirkungen.
Konsequenzen für das Licht am Arbeitsplatz
Am Arbeitsplatz müssen die Lichtbedingungen vor allem
bezüglich visuellem Komfort optimal abgestimmt werden.
In letzter Zeit spielen aber auch die nicht-visuellen Lichtwirkungen zunehmend eine grössere Rolle. Aufgrund der neuen Forschungsresultate wie Lichtqualität und Wohlbefinden
zusammenhängen, hat die Lampenindustrie ein neues Geschäftsfeld entdeckt. So erhofft man sich positive Effekte
auch von besserem Licht am Arbeitsplatz. Ob diese Hoffnung berechtigt ist, haben Forscher der Universität Surrey
in einem Bürogebäude in England untersucht. Sie bestrahlten je ein Stockwerk zuerst vier Wochen mit weissem Licht
und dann vier Wochen mit blau angereichertem Licht oder
umgekehrt. Sowohl Aufmerksamkeit als auch Gemütslage, Leistung, Konzentration und Sehkomfort waren beim
blauweissen Licht signifikant verbessert. Auch konnten die
Probanden in der Nacht besser schlafen. Wichtige Lichtquellen im Büro sind nicht nur Lampen, sondern auch die
Bildschirme. Biologisch besonders aktiv sind Modelle der
neueren Generation mit LEDs, denn sie emittieren stark
im blauen Wellenlängenbereich. Neben der geistigen Leistungsfähigkeit wie oben erwähnt, wirken LED Bildschirme
auch auf physiologische Messgrössen beim Menschen wie
zum Beispiel die abendliche Produktion des Dunkelhormons Melatonin und die elektro-enzephalographisch gemessene Hirnaktivität (siehe 1).
Neben der Lichtgestaltung mit künstlichem Licht im Büro
ist aber auch der Einbezug von natürlichem Tageslicht sehr
wichtig. Schon 1971 definierte der Biologe Stephen Boyden
das Bedürfnis nach Tageslicht als eine der "well-being
needs": als Voraussetzung für ein Leben ohne stressbedingte Krankheiten. Man weiss, dass Mitarbeiter, die wenig
Tageslicht abbekommen, unzufriedener und gesundheitlich
anfälliger werden (Berliner Ergonomic Instituts für Arbeitsund Sozialforschung). Darum arbeiten Physiker, Lichtplaner,
Architekten und Chronobiologen fieberhaft an ausgeklügelten Systemen und Gebäudegrundrissen, um das Tageslicht
bis in hinterste Zimmerwinkel zu leiten. Eine ideale Lösung
wäre, eine biodynamische Lichtquelle am Arbeitsplatz zu
haben, die punkto Intensität und Wellenlänge (Farbe) dem
3. Licht macht helle.
Neue Untersuchungen zeigen, dass Licht auch direkte
Auswirkungen auf die kognitive Leistungsfähigkeit von
Menschen hat. Wir konnten zum Beispiel feststellen, dass
Versuchspersonen, die eine Lernaufgabe vor einem mit
Leuchtdioden (LED) mit vielen Blauanteilen bestückten
Abbildung 3. Positive
Wirkung von LED Computerbildschirmen auf
höhere kognitive Funktionen im Vergleich zu
nicht-LED Computerbildschirmen, die weniger Blauanteile im
Lichtspektrum haben.
48
Communications de la SSP No. 37
allerdings, dass es für eine solche Richtlinie noch zu früh
ist. Es sind noch zu viele Fragen offen, und es mangelt an
Studienergebnissen, um sich derart festzulegen. Es ist aber
sehr positiv, dass neben den visuellen Aspekten nun vermehrt die Wirkungen des Lichts auf die innere Uhr und deren Regulation des Schlaf-Wachrhythmus, der kognitiven
Leistung sowie der Stimmung berücksichtigt werden, denn
Licht ist mehr als nur Helligkeit.
natürlichen Wechsel des Tagelichts möglichst nahe kommt.
Denn evolutionsgeschichtlich gesehen, wurde der Mensch
nicht fürs Büro konzipiert. Für uns wäre es normal, wenn
wir tagsüber draussen im Hellen wären. Einen sehr innovativen Ansatz, dieses Dilemma zu entschärfen, kommt
derzeit vom Fraunhofer Institut, das eine dynamische Lichtdecke mit Tausenden kleiner LEDs entwickelt hat, welche
dem Büroangestellten das Gefühl vermittelt, unter freiem
Himmel zu arbeiten (http://www.fraunhofer.de/en/press/research-news/2012/january/sky-light-sky-bright.html). Erste
Untersuchungen zeigen, dass ein solches Lichtszenario vor
allem bei der Verrichtung von kreativen Arbeiten am Computer auf grossen Anklang stösst.
Neben dieser kreativen technischen Lösung der Bürobeleuchtung versucht man eine nüchterne Vornorm zu erstellen, um die wichtige Begriffe zur cirkadianen, nicht-visuellen Wirkung von Licht auf den Menschen zu klären (DIN
V 5031-100). Das Ziel ist es, aufzeigen, wann und wie biologisch wirksame Beleuchtung einzusetzen ist, und wie viel
wirksamer sie ist als normales Licht. Viele Forscher glauben
Prof. sc. natw. Christian Cajochen leitet das Zentrum
für Chronobiologie an der Psychiatrischen Universitätsklinik in Basel. Seine Forschungsinteressen umfassen die circadiane und homöostatische Regulation
der Schlaf/Wachrhythmik beim Menschen, die nichtvisuelle Lichtwirkung in der Chronobiologie, sowie
circadiane Schlaf-Wachstörungen bei psychiatrischen
Patienten.
Lighting Application for Non-Visual Effects of Light
Andreas Wojtysiak, Alfred Wacker and Dieter Lang, Osram AG
Introduction
sponse is the curve for nocturnal melatonin suppression.
Several models have been developed to describe this response with minor deviations when these were used to rate
white light with respect to its circadian input. The models of
Gall [5] and Rea [6] differ with respect to the effect of light
in the green wavelength region, which might be of interest
when comparing small waveband (colored) light sources.
In total, it can clearly be stated, that blue spectral components in light act on the internal clock system by affecting
circadian amplitude and phase.
The discovery of melanopsin containing retinal ganglion
cells with intrinsic photoreception (ipRGC) at the beginning
of this millennium [1, 2, 3] evoked interest not only in the
research community, but also in the lighting industry. Beneficial health effects of light have been discussed not only
since evidence for the use of light in psychiatric disorder
therapy was achieved. One obvious drawback for broader
application was always the need for additional energy, because clear effects with the typical light used for illumination purposes were dependent on higher illumination levels.
It now has turned out, that the lighting used in previous laboratory and application studies was not sufficiently adapted to the non-visual reception system and cofactors could
have masked these effects considerably. Though there is
still discussion about the optimal lighting for non-visual effects with minimum energy use, there is no doubt in the
scientific community that appropriately timed stimulation of
the ipRGC during the day and avoidance of stimulation in
the night stabilizes our circadian system. This leads to a
more efficient nocturnal sleep and better daytime activity
and alertness levels. Alertness is also directly affected by
input to the ipRGCs, resulting in acutely increased performance in laboratory testing and higher activity levels in corresponding nuclei of the brain [4]. This article will highlight
how to transfer scientific results on non-visual effects - also
called biological effects - of light into lighting application.
Fig. 1: action spectrum c() for biological effects and visual sensitivity curve v() combined from different sources.
The model from Gall [5] was implemented in the German
prestandard DIN V 5031-100:2009 [7], which contains
terms and definitions for biological effects of light. Using the metrics described there, it is possible to rate lamp
spectra according to their biological efficiency in addition
to light output for vision. A lamp spectrum with a higher socalled biological action factor (abiol v ≥ 0,8) has a high fraction of short wavelength spectrum, a high correlated color
Lighting Technology for non-visual effects
Light Sources
A number of studies on the ipRGC have shown that the
action spectrum of their photopigment melanopsin peaks
in the blue spectrum around 480 nm. No nervous cell responses were elicited by yellow or red light. The best described action spectrum for a more complex biological re49
SPG Mitteilungen Nr. 37
is clear that the dynamics of daylight follows a rhythmic
change in the course of day and night, and that this is a
benchmark for good artificial lighting also. For day time application, changes in biological efficiency of applied lighting
with positive impact on circadian rhythm stability, sleep/
wake cycle, alertness and cognitive performance can be
achieved with light management technology already available. The biological effectiveness in nature emanates from
a combination of spectral composition and illuminance
level, being in average at highest level around noon and at
minimum in the night. Technically, this situation can be simulated by dimming the relative contribution of lamps with
different light colors against each other in order to have a
white light color but with different portions of blue spectral
components appropriate to the respective daytime.
temperature, and is generally more suitable to represent the
active and day time part of the circadian day, especially in
the morning hours. Cool white light sources including LEDs
and fluorescent lamps may be used for this purpose. While
stabilizing circadian rhythms when applied over the day,
this spectrum is not suited for the regenerative and nocturnal phases, typically in the late evening and night. Warm
white lamps with low biological action factors (abiol v ≤ 0,4)
have a lower influence on the ipRGCs and on the internal
clock. These lamps are more suited when light for vision is
needed, but an influence on the circadian phase or an alerting effect should be avoided. Halogen lamps, warm white
LEDs or fluorescent lamps are suited to achieve this.
To balance best with visual and ecological needs, it seems
advisable to use different CCT lamps or light sources with
high energy efficiency over the day and use them as needed. This will result in higher installation costs in the short
term, but will be the most sustainable solution in the long
run.
Warm colors with only little biological effects can maintain
good vision without strongly influencing circadian effects
in the evening, while cooler colors with enriched blue content used over the day are providing good vision and higher
biological effectiveness simultaneously. The evening and
night scenario also allows to reduce the laminar light distribution and a change to spot-like illumination exclusively.
This allows also substantial reductions in amount of energy
needed for lighting, as only the visual tasks and emotional
aspects have to be respected in these hours. Reductions
in energy consumption may further be achieved by including sensors and intelligent controls, without deductions in
illumination quality.
Luminaires
The biological photoreceptors are widely distributed over
the eye’s retina and more sensitive in the nasal and inferior
region than in the upper part [8]. For biological effects it is
essential to address many of these receptors, like the sky
does in nature. Good effects indoors will be achieved with
light coming from the upper field of view and covering a
wide solid angle, e. g. from the ceiling and the upper surfaces of walls. Consequently, biologically effective illumination requires planning and luminaires fitting to this concept,
with a high proportion of indirect lighting or laminar design,
thus leading to suitable vertical illumination levels. Up to
now, no dose-response curve describing the relationship
between lighting area and biological effect size has been
established. In the meanwhile, the general recommendation for application must be to "maximize" the lighting area,
while keeping luminance levels low in order to avoid glare
effects.
Lighting Application Studies
Application studies (like the examples below) showed, that
non-visual effects of light may be achieved with moderate
effort in energy consumption by using modern lighting systems and control. The general strategy is to differentiate
lighting according to time of the day and needs.
Controls and Light Management Systems (LMS)
Natural daylight is highly variable, especially in terms of illuminance levels but also in terms of color temperature. It
Better lighting in nursing homes improved the nocturnal
sleep and daytime activity as well as psychological scores
of elderly persons in several studies [9, 10]. Old persons are
especially dependent on a lighting change because of their
reduced transmission of the dioptric apparatus. The hazing
and yellowing of the lenses with age reduces drastically the
Fig. 2: Lighting concept with pendant luminaires for day-time office workers including non-visual effects of light:
Left: Day scenario with task lighting by warm white direct light and
additional cool white light to the ceiling and upper wall to address
ipRGC. Right: Evening and night scenario with warm white task
lighting only.
50
Communications de la SSP No. 37
short wavelength light arriving at the retina. This effect was
counteracted by the lighting.
Jet Lag and Shift Work
Natural light sets the internal clock, but humans often challenge this system with more or less voluntary changes in day/night behavior. Jet travel is such
a challenge, shift work is another. The internal clock
shifts about 1 hr per day in such scenarios. With timed
biologically active light (as described in the main text)
and avoidance of light at other appropriate times, it
appears possible to adapt to a new time zone much
faster. Shifts of more than 3 hrs with one light episode
have been achieved in laboratory settings [a]. But at
present, there is no reliable and robust scientific base
how to handle lighting for shift workers. Actual recommendations range from shortening the shift schedules
in order to reduce frequent massive circadian disruption as stated by some ergonomics experts to shifting totally (also in the worker’s free times) to the new
shift schedule as proposed by chronobiologists, with
considerable consequences for social life of those affected [b].
A stronger synchronization by daytime office light and improvements in subjective performance in office workers
have been achieved with fluorescent lamps of higher CCT
than the typical 4000 K lamps used in this application [11,
12]. For daytime indoor workers, this could be a first step
to a better lighting but it is needed to say that this scenario
might not be optimal for late office hours.
Comparable benefits have been shown in schools, leading to increased scholar performance of the pupils and in
hospital settings, where the recovery phase could be shortened.
Conclusion
Although scientific researchers still have numerous questions in this field, these first results of application of the new
findings on non-visual effects of light open a very promising future for improvements in interior illumination. This is
true for the professional lighting as well as for the lighting
at home.
[a] Khalsa, S. B., M. E. Jewett, et al. (2003). "A phase response
curve to single bright light pulses in human subjects." J Physiol 549
(Pt 3): 945-52.
[b] Roenneberg, T. (2009): "New approaches in investigating the
consequences of shift-work". 3rd DIN Expert Panel Effect of Light
on Human Beings, DIN. Berlin, Beuth Verlag.
References
[1] Brainard, G. C., et al. (2001). "Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor." J Neurosci
21(16): 6405-12.
[2] Thapan, K., et al. (2001). "An action spectrum for melatonin suppression: evidence for a novel non-rod, non-cone photoreceptor system in humans." J Physiol 535 (Pt 1): 261-7.
[3] Berson, D. M., et al. (2002). "Phototransduction by retinal ganglion cells
that set the circadian clock." Science 295(5557):1070-3.
[4] Vandewalle, G., P. Maquet, et al. (2009). "Light as a modulator of cognitive brain function." Trends Cogn Sci 13(10): 429-38.
[5] Gall, D., Bieske, K. (2004). Definition and measurement of circadian
radiometric quantities. CIE Symposium '04: Light and Health: non-visual
effects, University of Performing Arts, Vienna, CIE.
[6] Rea, M. S., et al. (2005). "A model of photo¬transduction by the human
circadian system." Brain Res Brain Res Rev 50(2): 213-28.
[7] DIN V 5031-100:2009-06 Optical radiation physics and illuminating engineering - Part 100: Non-visual effects of ocular light on human beings
- Quantities, symbols and action spectra
[8] Glickman, G., et al. (2003). "Inferior retinal light exposure is more effective than superior retinal exposure in suppressing melatonin in humans." J
Biol Rhythms 18(1):71-9.
[9] Van Someren, E. J., A. Kessler, et al. (1997). "Indirect bright light improves circadian rest-activity rhythm disturbances in demented patients." Biol
Psychiatry 41(9): 955-63.
[10] Riemersma-van der Lek, R. F., D. F. Swaab, et al. (2008). "Effect of
bright light and melatonin on cognitive and noncognitive function in elderly residents of group care facilities: a randomized controlled trial." JAMA
299(22): 2642-55.
[11] Vetter, C., M. Juda et al. (2011) “Blue-enriched office light competes
with natural light as a zeitgeber”; Scand J Work Environ Health 37(5): 437445
[12] Viola, A. U., L. M. James, et al. (2008). "Blue-enriched white light in
the workplace improves self-reported alertness, performance and sleep
quality." Scand J Work Environ Health 34(4): 297-306.
Andreas Wojtysiak ist promovierter Biologe und nach
Tätigkeiten am IMST in Kamp-Lintfort, in der Medizinischen Fakultät der privaten Universität Witten/Herdecke und bei BenQ Mobile in München seit 2008
bei der Osram AG München als Innovation Manager
Light & Health beim Strategic Innovation Management
(SIM) aktiv.
Alfred Wacker (Dipl.-Ing.) war früher Leiter des Marketings bei OSRAM und ist nun für seine Firma beratend und in internationalen Gremien und Komitees
tätig, u. A. im "Lighting Technology Standards Committee NA 058-00-27 AA (FNL 27) 'Effects of light on
human beings' at DIN", dem auch die Schweiz angehört.
Dieter Lang (Dipl.-Phys.) forschte früher bei Osram
an "ceramic metal halide lamps" und ist seit der Formierung des Corporate Innovation Management Department im Jahr 2004 als Head Europe zuständig für
Innovationen.
51
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