Download Friction in Physics and Society - The Racah Institute of Physics

American Physical Society
Racah Institute of Physics
Workshop
Friction in Physics and Society
“Little Jerusalem”, The Ticho house
(12.12.12 @ 12.12)
A mistake of a Genius
(An example of mixed friction –
both in physics and society)
To the 90th anniversary of two famous Nobel
prizes in Physics
Amusia M. Ya.
The Hebrew University, Jerusalem
The Nobel Prize in
Physics 1921
"for his services to Theoretical Physics, and
especially for his discovery of the law of the
photoelectric effect"
Albert Einstein
Germany and Switzerland
Kaiser-Wilhelm-Institut (now Max-PlanckInstitut) für Physik Berlin, Germany
Albert Einstein received his Nobel Prize one year
later, in 1922. During the selection process in
1921, the Nobel Committee for Physics decided
that none of the year’s nominations met the
criteria as outlined in the will of Alfred Nobel.
According to the Nobel Foundation's statutes, the
Nobel Prize can in such a case be reserved until
the following year, and this statute was then
applied. Albert Einstein therefore received his
Nobel Prize for 1921 one year later, in 1922.
The Nobel Prize in
Physics 1922
"for his services in the investigation of the structure
of atoms and of the radiation emanating from them"
Niels Henrik David Bohr
Denmark
Copenhagen University, Copenhagen, Denmark
Awarded equations
• Einstein’s , 1905 h
 I
“On a Heuristic Viewpoint Concerning the
Production and Transportation of Light” , Annalen
der Physik 17 (6), p. 132–148
• Bohr’s, 1913
1   2  h12
“On the Constitution of Atoms and Molecules”,
Philosophical Magazine 26 (1), p. 476.
Today’s view: energy conservation low in discrete
and continuous spectra
Was “Photoeffect” almost trivial
for Einstein, generally accepted
by public and thus awarding this
work was a sort of a
compromise?
Not at all!
First Verifications of Einstein’s
equation
• Energy conservation – R. Millikan, 1915
• Momentum conservation – A. Compton,
1919
Both had non-Einsteinian
Interpretation, based on theories of
J.J. Thomson, A. Sommerfeld 19101913
• Strong opposition of N. Bohr
Acceptance / non-acceptance
“That he has occasionally speculated too
far (for example, his hypothesis
concerning light quanta), should not be
held against him since he who takes no
such risks will not be able to make really
novel contributions to science”
Planck, Nernst, Rubens, Warburg,
12 June 1913, from: Nomination to the
Prussian Academy of sciences membership
From Bohr’s Nobel Lecture (1):
Einstein was led to the formulation of the so-called
"hypothesis of light-quanta", according to which the radiant
energy, in contradiction to Maxwell’s electromagnetic theory
of light, would not be propagated as electromagnetic waves,
but rather as concrete light atoms, each with an energy equal
to that of a quantum of radiation. This concept led Einstein to
his well-known theory of the photoelectric effect. This
phenomenon, which had been entirely unexplainable on the
classical theory, was thereby placed in a quite different light,
and the predictions of Einstein’s theory have received such
exact experimental confirmation in recent years, that perhaps
the most exact determination of Planck’s constant is afforded
by measurements on the photoelectric effect.
From Bohr’s Nobel Lecture (2):
This phenomenon, which had been entirely
unexplainable on the classical theory, was
thereby placed in a quite different light, and the
predictions of Einstein’s theory have received
such exact experimental confirmation in recent
years, that perhaps the most exact
determination of Planck’s constant is afforded
by measurements on the photoelectric effect.
From Bohr’s Nobel lecture (3):
In spite of its heuristic value, however, the
hypothesis of light-quanta, which is quite
irreconcilable with so-called interference
phenomena, is not able to throw light on the
nature of radiation. I need only recall that these
interference phenomena constitute our only means of
investigating the properties of radiation and therefore
of assigning any closer meaning to the frequency
which in Einstein’s theory fixes the magnitude of the
light-quantum.
Battle of Giants I
“This is my most revolutionary paper”
A Einstein’s (no ether, yes quanta, duality)
One should compare to presented above quotation:
“In spite of heuristic value, however, the hypotheses of
light quanta, which is quite irreconcilable with socalled interference phenomena, is not able to throw
light on the nature of radiation”,
Bohr’s Nobel lecture, 1922
Battle of Giants II
1.Frequency in Photoeffect equations comes not
from quantum picture but from wave
interference
2.Einstein laws are complimentary to classical
picture and are valid on the average
N. Bohr, H. Kramers, and J. Slater, Quantum
Theory of Radiation, Phil. Mag., 47, 785, 1924
Battle of Giants:
The End
• Confirmation of Photoeffect: Millikan, 1916
• Photon energy-momentum conservation:
Coincidence experiment
in Compton effect
W. Bothe and H. Geiger, 1925
A. Compton and A. Simon, 1925 …
W. Gross and N. Ramsay, 1950!
Aftershock 1
• Bohr tried to apply his ideas on violation
of energy conservation in elementary
processes to explain continuous
spectrum of electrons in  -decay
(1930) “n → p + e”
• Pauli in 1930 suggested a new particle,
neutral and very light particle v, that
explains the controversy
•
“n → p + e + v”
Aftershock 2
• Pauli was correct. The conservation in
microscopic processes has been saved. A
new particle was predicted and later
detected
• Pauli in 1930 suggested a new particle,
neutral and very light particle v, that
explains the controversy
•
“n → p + e + v”
Aftershock 3
Pauli’s letter to “radioactivists” (1930): I admit
that my remedy may appear to have a small a
priori probability because neutrons, if they
exist, would probably have long ago been
seen. However, only those who wager can
win, and the seriousness of the situation of
the continuous  -spectrum can be made clear
by the saying of my honored predecessor in
office, Mr. Debye, "One does best not to think
about that at all, like the new taxes."
Concluding remarks
• Einstein and Maxwell pictures peacefully coexist, in respective domains
• Conservation laws are the fundament of our
understanding of physical processes at any
size of the objects
• Mistakes of a genius are by itself a great
achievement that was confirmed by the BohrEinstein second, well-known debate in the
thirties, where Bohr was the winner
• Thank you very much for patience
and attention
PS: Einstein on Quantum mechanics 1
There is no doubt that quantum mechanics
has seized hold of a beautiful element of truth
and that it will be a touchstone for a future
theoretical basis in that it must be deducible
as a limiting case from that basis just as
electrostatics is deducible from the Maxwell
equations of the electromagnetic field or as
thermodynamics is deducible from statistical
mechanics.
PS: Einstein on Quantum mechanics 2
However, I do not believe that quantum
mechanics will be the starting point in the
search for this basis, just as one cannot
arrive at the foundations of mechanics from
thermodynamics or statistical mechanics. Journal of the Franklin Institute, 221, 313,
1936
The result of Einstein - Bohr lifelong debate:
1:1