The document discusses various interpretations and aspects of quantum mechanics. It explores interpretations like the Copenhagen interpretation, hidden variable theories, the many worlds interpretation, and issues like wave function collapse and decoherence. It also discusses open questions like the nature of reality according to quantum mechanics and the relationship between the quantum realm and classical physics.

1. Quantum mechanics,
Reality,
&
You
John Ashmead

2. QM-RAY
•“Behold the weird”
•The collapse of the collapse of the wave
function
•Existential quantum mechanics
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

3. “Behold the weird”
•Double slit experiment
•Uncertainty principle
•Checkpoint Copenhagen
•Schrödinger’s Cat
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

4. Double slit
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

5. Uncertainty
principle
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

6. Copenhagen
interpretation
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

7. Schrödinger's Cat
One can even set up quite ridiculous cases. A cat is penned up in a steel
chamber, along with the following diabolical device (which must be secured
against direct interference by the cat)…
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

8. The collapse of the collapse
of the wave function
•Collapse real
•Hidden variables
•Multiverse
•Shut-up-and-calculate
•“That which does not destroy you…”
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

9. Objective collapse
•Wigner’s Calibrated Panel of Infants
•The all collapse all the time channel
•Penrose finds decoherence in a grain of
sand
•The case of the highly charged cat
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

10. Wigner’s
Panel of infants
1. Perception
counts as
consciousness.
2. Consciousness
induces
deviations from
laws of physics.
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

11. Unified dynamics for microscopic &
macroscopic systems (1986)
- Ghirardi, Rimini, Weber
•Eliminate special role of observer
•Posit an interaction which is non-linear,
stochastic, & depends on surround
•Get a GRW collapse perhaps every 100
million years
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

12. The road to reality
• Tiny mirror in two
states at once
• With gravity involved,
this costs energy
• Forcing it to pick one of
the two states.
• And causing the beam
to lose coherence
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

13. Highly charged cat
Charge up your Let its wave function diffuse
cat
Observe your cat Accelerated charges
radiate
Tune
your
radio
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

14. Hidden variables
•Statistic
interpretation
•Einstein-
Podolsky-
Rosen: elements
of reality
•Bell’s theorem
•Bohmian
mechanics
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

15. Einstein podolsky rosen
You can’t know both x-spin & z-spin at the
same time, & yet you can.
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

16. Bell’s Theorem
Measure along x, or
along z, or along
their bisector, but
only one
measurement (of
each spin) per
round
One poke per
measurement
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

17. Information Distance
Information distance Information distance
from A to B is the obeys the triangle
uncertainty left in B inequality
when A is known. d ( A,C ) ≤ d ( A, B ) + d ( B,C )
B
d ( A, B ) d ( B,C )
A C
d ( A,C )
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

18. Information ZigZag
1.0
θ left θ right
0.8
0°
0.6
0.4 .020
.0
0.2 10°
50 100 150 .020 .064
( ) ( )
d (θ ) = − lg cos 2 (θ 2 ) cos 2 (θ 2 ) − lg sin 2 (θ 2 ) sin 2 (θ 2 )
p ≡ cos 2 (θ 2 ) 20°
θ = 10° → p (θ ) ≈ 99%, d ≈ .020
θ = 20° → p (θ ) ≈ 96%, d ≈ .064
.064 > .020 + .020 Violates triangle inequality!!!
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

19. The right way to get
it wrong
Nick
Herbert’s
Faster-Than-
Light
Telegraph
June 2012,
Scientific
American
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

20. Bohmian Mechanics
• Well-defined
particles
• Guided by a pilot
wave that obeys
Schrödinger
equation
• Problems with
many particles,
high energies
• Popular, if weird
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

21. Multiverse
•Many worlds, many minds, many
words
•Quantum suicide/a plethora of
observers
•Splitting headaches
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

22. Universes Fork
Observers fork too
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

23. Experimental tests
• Quantum suicide
• Count of observers (many minds) has implications
• Leakage between universes
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

24. Splitting headaches
• Why this set of alternatives &
not that?
• When does split happen?
• How does split happen?
• That’s rather a lot of
"I am glad of all details," universes, isn’t it?
remarked my friend,
"whether they seem to • What counts as an observer?
you to be relevant or
not." • Can different universes chat?
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

25. Shut-up-&-calculate
•Arguably most popular
•Let the pencil do the
thinking. Or
Mathematica.
•Pencils a bit short on
imagination sometimes.
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

26. “What we call
`reality’ consists of
an elaborate
papier-maché
construction of
imagination and
theory fitted in
between a few iron
posts of
observation.”
- John A. Wheeler
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

27. Many Interpretations
• Deterministic
• Wave function real
• Hidden variables
• Collapse real
• Observer part of
interpretation
• Local/non-local
• Time symmetric
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

28. “That which does not destroy you
makes you strong”
• 27+ rival
interpretations
•Critics such as
Wigner, Bell,
Einstein, …
•300+ foundational
experiments
(Auletta)
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

29. Existential Quantum
mechanics
•The wave function needs no interpretation
•Decoherence
•Radical conservatism
•At the edge of the known
•A game of chess
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

30. Pusey, Barrett, &
Rudolph •The quantum state of
a system can be
inferred uniquely
from the physical
state
•Provided the
predictions of
quantum mechanics
are correct. (They
are.)
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

31. Decoherence
How does
classical
definiteness
emerge
from the
quantum
sea?
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

32. Decoherence still
cohering
•Toy cases
•Bound states
•Quantum Zeno effect
•Stochastic resonance
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

33. Radical
conservatism
Be conservative by
sticking to well-
•Cat states
established physical •Long range entanglement
principles, but probe
them by exposing •Phonons
their most radical
conclusions. •Bose-Einstein condensates
- J. A. Wheeler
•Majorana fermions
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

34. At the edge of the
known
•Entropic gravity
•Origin of the
universe
•Dark flow
•Whispering
gallery of the
multiverse
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959

35. A game of chess
•Multiple
levels of
analysis
•Appropriate
mathematics
http://research.cs.queensu.ca/Parallel/
QuantumChess/QuantumChess.html
•Your move!
QM, Reality, & You - John Ashmead - May 27th, 2012 - Balticon http://timeandquantummechanics.com/?p=959