quantum mechanics, reality, & you

Quantum mechanics, Reality,

& You

John Ashmead

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

QM-RAY

•“Behold the weird”

•The collapse of the collapse of the wave function

•Existential quantum mechanics

http://www.timeandquantummechanics.com



“Behold the weird”

•Double slit experiment

•Uncertainty principle

•Checkpoint Copenhagen

•Schrödinger’s Cat




Double slit




Uncertainty principle




Copenhagen interpretation




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)…




•Collapse real

•Hidden variables

•Multiverse

•Shut-up-and-calculate

•“That which does not destroy you…”

The collapse of the collapse of the wave function




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




Wigner’s Panel of infants

1. Perception counts as consciousness.

2. Consciousness induces deviations from laws of physics.





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




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




Highly charged catCharge up your

catLet its wave function diffuse

Observe your cat Accelerated charges radiate

Tune your

radio




•Statistic interpretation

•Einstein-Podolsky-Rosen: elements of reality

•Bell’s theorem

•Bohmian mechanics

Hidden variables




Einstein podolsky rosen

You can’t know both x-spin & z-spin at the same time, & yet you can.




Bell’s Theorem

One poke per measurement

Measure along x, or along z, or along their bisector, but

only one measurement (of

each spin) per round




Information Distance

A

B

C

Information distance from A to B is the

uncertainty left in B when A is known.

Information distance obeys the triangle

inequalityd A,C( ) ≤ d A,B( ) + d B,C( )

d A,C( )

d A,B( ) d B,C( )




Information ZigZag

d θ( ) = − lg cos2 θ 2( )( )cos2 θ 2( ) − lg sin2 θ 2( )( )sin2 θ 2( )50 100 150

0.2

0.4

0.6

0.8

1.0

θ = 10°→ p θ( ) ≈ 99%,d ≈ .020θ = 20°→ p θ( ) ≈ 96%,d ≈ .064

θleft θright0°

10°

20°

.020

.020

.0

.064

.064 > .020 + .020

p ≡ cos2 θ 2( )

Violates triangle inequality!!!




The right way to get it wrong

Nick Herbert’s

Faster-Than-Light

TelegraphJune 2012, Scientific American




Bohmian Mechanics• Well-defined

particles

• Guided by a pilot wave that obeys Schrödinger equation

• Problems with many particles, high energies

• Popular, if weird




Multiverse

•Many worlds, many minds, many words

•Quantum suicide/a plethora of observers

•Splitting headaches




Universes Fork

Observers fork too




Experimental tests

• Quantum suicide

• Count of observers (many minds) has implications

• Leakage between universes




Splitting headaches• Why this set of alternatives &

not that?

• When does split happen?

• How does split happen?

• That’s rather a lot of universes, isn’t it?

• What counts as an observer?

• Can different universes chat?

"I am glad of all details," remarked my friend, "whether they seem to you to be relevant or not."


Shut-up-&-calculate

•Arguably most popular

•Let the pencil do the thinking. Or Mathematica.

•Pencils a bit short on imagination sometimes.




“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




Many Interpretations• Deterministic

• Wave function real

• Hidden variables

• Collapse real

• Observer part of interpretation

• Local/non-local

• Time symmetric




“That which does not destroy you makes you strong”

•27+ rival interpretations

•Critics such as Wigner, Bell, Einstein, …

•300+ foundational experiments (Auletta)




Existential Quantum mechanics

•The wave function needs no interpretation

•Decoherence

•Radical conservatism

•At the edge of the known

•A game of chess




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.)




Decoherence

How does classical

definiteness emerge

from the quantum

sea?




Decoherence still cohering

•Toy cases

•Bound states

•Quantum Zeno effect

•Stochastic resonance




Radical conservatism

•Cat states

•Long range entanglement

•Phonons

•Bose-Einstein condensates

•Majorana fermions

Be conservative by s t i ck i ng to we l l -established physical principles, but probe them by exposing their most radical conclusions.- J. A. Wheeler




At the edge of the known

•Entropic gravity

•Origin of the universe

•Dark flow

•Whispering gallery of the multiverse




A game of chess

•Multiple levels of analysis

•Appropriate mathematics

•Your move!http://research.cs.queensu.ca/Parallel/QuantumChess/QuantumChess.html



http://research.cs.queensu.ca/Parallel/QuantumChess/QuantumChess.html




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