Download TED

Too Beautiful Not to be True:
The Hidden Logic of Quantum Mechanics
Avshalom C. Elitzur
Copyleft
Permission is granted to everyone to copy and/or use this work or any part of it.
Abandon hope all ye who enter here
Dante
Determinism
Objectivity
Locality
Schrödinger
© Jie Qi
crest
trough
“in phase”
crest
constructive
interference
trough
crest
trough
“out of phase”
crest
trough
destructive
interference
The Double-Slit Experiment
(Courtesy of Tel-Aviv Municipality)
Constructive
Destructive
Constructive
interference
Proof: Light=Waves
Interference of water waves
Interference of light waves
The Mach-Zehnder Interferometer:
•
Photon is emitted and split into two
•
Reflected back (notice phase shift upon reflection!)
•
One half split again
•
Second half split again (at the same time)
•
Destructive Interference on detector D
•
Constructive Interference on detector C
•
All light reaches detector C.
detectors
C
D
half-silvered mirrors
solid mirrors
light source
Confused? Don’t worry: It will soon get much worse.
Interference occurs with single
Can we outsmart the “which path” uncertainty?
1. Photons
2. Electrons
Interference
3. Neutrons
0%
100%
4. Atoms
5. Molecules
6. …
0
1
1
0
50%
Can we outsmart the “which path” uncertainty?
Interference
0%
100%
50%
Can we outsmart the “which path” uncertainty?
50%
50%
50%
Can we outsmart the “which path” uncertainty?
50%
50%
50%
Can we outsmart the “which path” uncertainty?
Interference
0%
100%
Meet the Uncertainty
h
Principle: xp 
2
Interference
0%
100%
Heisenberg
position unknown
?
?
Meet the Uncertainty
h
Principle: xp 
2
Interference
0%
100%
momentum lost
Heisenberg
position known
Can we outsmart the “which path” uncertainty? No, but
Nam et Ipsa Ignorantia
Scientia Potestas Est*
*Knowledge Ignorance begets power 
Interaction-Free Measurement:
The Elitzur-Vaidman (1993) Bomb-Testing Experiment
1. Photon emitted
2. Split
3. No Boom
4. Remaining wave splits
5. “Forbidden” detector D clicks
D
C
A New Monster is Born
What was I thinking…
© Ted Dawson
The Einstein-Podolsky-Rosen Experiment
Classical analogue: Two coins
?
?
The Einstein-Podolsky-Rosen Experiment
Quantum version: Two particles
The Einstein-Podolsky-Rosen Experiment
Quantum version: Two particles
Or
Bell’s Test for Particle Telepathy:
3 Possible Questions, 2 Possible Answers
1. Is your spin “up” in the α direction?
50% “Yes” , 50% “No”
2. Is your spin “up” in the β direction?
50% “Yes” , 50% “No”
3. Is your spin “up” in the γ direction?
50% “Yes” , 50% “No”
Overall: 100% correlations for same-question pairs
but 50% correlations for different-question pairs!
pre-established agreement would give higher correlations!

“Telepathy” between particles proved
A quantum dynasty
Bohm
Aharonov
Vaidman
Elitzur
Dolev
Bell’s Test for
Particle Liar
Telepathy:
The Elitzur-Dolev
Quantum
Paradox:
3Replacing
Possible Questions,
2 Possible
Answers
Bell’s Third
Question
1. Is your spin “up” in the α direction?
50% “Yes” , 50% “No”
2. Is your spin “up” in the β direction?
50% “Yes” , 50% “No”
youspin
entangled
other particle?
3. Are
Is your
“up” in with
the γ the
direction?
50% “Yes” , 50% “No”
The Quantum Liar Paradox
1
 A1* A2  A1 A2 *
2

•
Two excited atoms A1 and A2 reside
in cavities facing a beam-splitter
•
One detector clicks, source of the
photon uncertain
•
Thereby entangling the two atoms
•
An orthogonal measurement to
excited/ground is introduced
•
EPR
•
Bell-inequality violated
•
The liar paradox all over again
The Quantum Liar Paradox
– One atom is found to be excited, which seems to indicate
that it emitted no photon.
– Hence, it could not interact with the other atom and should
not be entangled with it.
– But, by violating Bell’s inequality, its “having preserved its
photon” is due to entanglement with the other atom!
Which is equivalent to saying
THIS SENTENCE HAS NEVER
BEEN WRITTEN
:-)
Большая Советская Энциклопедия
Lavrentiy Beria
History, The Soviet Encyclopedia’s Version
When the “hero of the people” former KGB head is
shot as a traitor, you take back old volumes of the
encyclopedia, take out the pages of the entry
“Beria” and replace them with “Bering.”
Our Relativistic Quantum Model
Could Nature be similarly reiterating a process’s
evolution at the quantum level?
References
Dolev, S., & Elitzur, A.C. (2001) Non-sequential behavior of the wavefunction.
http://arxiv.org/PS_cache/quant-ph/pdf/0102/0102109v1.pdf
Elitzur, A.C., & Dolev, S (2006) Multiple interaction-free measurement as a
challenge to the transactional interpretation of quantum mechanics. In
Sheehan, D. [Ed.] Frontiers of Time: Retrocausation – Experiment and
Theory. AIP Conference Proceedings, 863, 27-44.
Elitzur, A.C., & Dolev, S (2007) The inexhaustible source of insights
revealed by every photon. Proceedings of SPIE Volume 6664: The Nature
of Light: What Are Photons?, C. Roychoudhuri, A.F. Kracklauer, & K.
Creath, Eds, 666402-666413.
http://a-c-elitzur.co.il/uploads/articlesdocs/photon5(2).pdf
What a pity to die at the dawn of relativity!
(Herman Minkowski, 1909)