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Quantum Illusions and Time

Quantum Illusions and Time. Joan Vaccaro. K. K. y. E. x. z. y. x. E. z. Quantum States. Photons (particles of light). polarisation of E (electric field): two orthogonal directions. E. y. x. z. y. E. x. z. E. y. x. y. x. z. E. z. arbitrary polarisation.

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Quantum Illusions and Time

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  1. Quantum Illusions and Time Joan Vaccaro K K

  2. y E x z y x E z Quantum States Photons(particles of light) • polarisation of E (electric field):two orthogonal directions

  3. E y x z y E x z E y x y x z E z • arbitrary polarisation • superpositionsplacement of “one thing on topof another” • measurement 50% PBS 50%

  4. y y E E x x z z • superposition of two positions opaque absorber with 2 slits upper d lower • verifying the superposition photons pile up here one at a time interference pattern but NOT here need many photons for verification

  5. Experiments Young photons 1802 Young electrons 1926 Davisson, Germer & Thomson atoms 1930 Estermann & Stern neutrons 1945 Wollan & Shull bucky balls 2002 Zeilinger virus? bacteria? flea? cat? people? Thomson Shull Zeilinger

  6. Tr(1), Pa(1) Tr(2), Pa(2) Tr(3), Pa(3) Tr(4), Pa(4) Many Worlds …first a bit of history… • 1920’s: treatment of radioactive decay radioactive atom possible tracks Tr() & paths Pa() of single particle cloud chamber but only one track per particle is seen

  7. Tr(3), Pa(3) Tr(4), Pa(4) Tr(1), Pa(1) Tr(2), Pa(2) Copenhagen Interpretation: • 1927: Bohr and Heisenberg in Copenhagen when experimenter looks at cloud chamber its state collapses see only one track

  8. 00:00 12 9 3 6 Schrödinger’s Cat radioactive atom + Geiger detector

  9. 09:30 12 9 6 Schrödinger’s Cat radioactive atom + Geiger detector hammer trips and breaks vial of poison cat dies

  10. 00:15 12 9 3 6 Schrödinger’s Cat radioactive atom + Geiger detector hammer trips and breaks vial of poison cat dies Partial decay leads to superposition state until experimenter looks inside box and state collapses hi kitty oh no… 50% chance 50% chance OR

  11. I don’t like it and I’m sorry I ever had anything to do with it. collapse is not described by any dynamical process(with forces, potentials etc.) Schrödinger hi kitty oh no… 50% chance 50% chance OR

  12. Everett 1957 (50th anniversary year) • applying quantum mechanics to universe (cosmology) • no external observers (experimenters) to collapse state • We need new toy example • don’t know how to treat“no life process”(dead) and “life process” (alive) as physical states

  13. 00:00 12 9 3 6 The cat that may (or may not) be fed

  14. 09:30 12 9 6 The cat that may (or may not) be fed 3

  15. 00:15 12 9 3 6 The cat that may (or may not) be fed Why don’t we see this superposition?

  16. This is what happens when we look… here kitty-kitty…

  17. This is what happens when we look… there you are you’ve over eaten you’re so hungry …so how do we see superpositions

  18. The dropped cat experiment (with catchers) - how to “see” a superposition interference probability

  19. The dropped cat experiment (with catchers) - how to “see” a superposition interference probability

  20. Parameters d = 0.1m x = 1m m = 10 kg L = 1067 m t = 1026 y The dropped cat experiment (with catchers) - how to “see” a superposition interference d L probability x

  21. we never even try to do this kind of experiment - need control (& disentangle atom… from cat etc.) - but, importantly, need to repeat it many times to build up interference pattern separate “worlds” evolve… you’ve fat! here’s food $ $$$ the poor but happy world the rich but sad world the perception of “one single world” is an illusion

  22. Many Times David Pegg’s quantum theory of time • canonical approach to quantising gravity • Wheeler-deWitt - equation: - universe is in a stationary state - no motion – frozen dynamics - energy is well known (zero) Pegg, J.Phys. A 24, 3031 (1991). prob. prob. X P • Heisenberg uncertainty principleif you know positionX well, momentumP is uncertain “ “ energyE “ timeT “ “time in the universe must be uncertain X P

  23. use new set of axes – each axis represents a different time 3 state of the universe axes chosen to make projections all equal 2 1 1 2 3 4 5 History vector – totality of reality – state at all times

  24. divide universe into 2 parts: Clock + Restclock must have equally spaced energy levels R C orthogonal clock states 1 M M+1 P find interval where Clock and Rest are separate and non-interacting • rewrite interval in terms of orthogonal clock states

  25. Rn+1 Rn Rn t  Rn Rn t M M+1 P R1 R2 R3 RP C R • the dynamics of Rest can be written in terms of the time parameter t defined by Clock: t =  Schrödinger’s equation for dynamics

  26. R1 R2 R3 RP C R we live at these different times the perception of “one present” is an illusion this illusion is on par with the single world illusion

  27. Puzzle: how does our perception of travelling in time arise? R1 R2 R3 RP these states of Rest are non-orthogonal so can’t be sure which one we are in Rm-1 Rm R Rm+1 • this gives a connection between different states of Rest • but the connection is the same in both directions!

  28. Puzzle: why do we travel in one direction in time? • anti-particles are the time reversed versions of particles time gamma ray photons electron e anti- electron e+ electron e anti- electron e+ electron e space • all anti-particle and particle pairs are time symmetric except for Kaons (K mesons)

  29. K0 K0 K0 antimatter  e+  K0 matter   + antimatter e K0 matter Neutral kaons K0 have a lifetime of less than 106 s. Decay paths: K0 e+ +  +   e + ++ positron pion neutrino (more likely) electron pion antineutrino • equal number of K0 and are found to yield different numbers of e+and e • violation of CP &  T symmetry (CERN 1998) R1 R2 R3 RP t K0 short lifetime long lifetime time asymmetric

  30. K0 R1 R2 R3 RP t K0 short lifetime long lifetime only unsure of which state in the “future” we are in Rm Rm-1 Rm+1 Kaons appear to be responsible for us travelling through time!!!

  31. RIP Conclusion Many worlds: we exist in many worlds but havethe illusion (and pleasures) of only one- but somewhere we are having a really good time Many times:we exist at many times but have the illusion of only onepresent whichmarchessteadily toward to our demise! - but consoled by knowingwe still exist at earlier times Free will: even our perception of free will is an illusion – we cant change the future because we already exist there (hopefully)- but we can enjoy the illusion

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