Quantum Mechanics, Reality, & You

Quantum mechanics, Reality, & You John Ashmead

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

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

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

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

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

Schrödingers 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

“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

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

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

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

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

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

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

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

Quantum Mechanics, Reality, & You

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