Outline Time’s Passage: Apparent? Real? Quantum Clues Relativistic Clues The Model

1. Where is Time Going? Some Novel Clues from Quantum Mechanics and RelativityPresented in “The Forgotten Present: A Quest for a Richer Concept of Time,”Munich-Pullach, Germany, April 29th - May 2nd, 2010.Avshalom C. Elitzur • Outline • Time’s Passage: Apparent? Real? • Quantum Clues • Relativistic Clues • The Model © Everyone 2010Permission is granted to everyone to copy and/or use this work or any part of it.

2. Outline • Time’s Passage: Apparent? Real? • Quantum Clues • Relativistic Clues • The Model

3. Time: The Common ViewEvents Become and Go, One by One

4. Time: The Relativistic ViewAll Events Coexist along Time

5. Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States

6. Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States

7. Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States

8. x t Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States

9. x t Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States “Now”

10. Relativistic Contraction is a Consequence of the “Coexistence” of Past and Future States “Now”

11. The Block Universe Account of Time All events – past, present and future – have the same degree of existence. There is no privileged “Now.”

12. Why Most Physicists Deny Becoming • It might entail a yet higher time (How fast does the “Now” move?) and so on to infinity of times • It seems to entail absolute simultaneity

13. Theoretical Lavishness of Superstring Theories: • Extra spatial dimensions • Hyperspaces • Multiverse • Etc. All within the Block Universe!

14. Taking Side πάντα χωρεῖ καὶ οὐδὲν μένει Heraclitus of Ephesus (535–475 BC) Parmenides of Elea (515 - 450 BC)

15. Outline • Time’s Passage: Apparent? Real? • Quantum Clues • Relativistic Clues • The Model

16. Quantum Spatial Peculiarities EPR Experiment E-V Experiment

17. Quantum Temporal Peculiarities HBT Experiment Schrödinger’s cat Delayed Choice

18. tf: Cat dead and decomposing tf: Cat alive, but lean and unhappy Schrödinger’s Cat as a Temporal Paradox OR t1: Lethal event occurring or not occurring t0: Cat and deadly machine sealed in box

19. The Hanbury-Brown-Twiss Effect • (HBT, 1958) Interference of two distant sources: • Even when the sources are so weak to produce a single photon at a time! • Coherent light emitted by two sources • Light is split by the beam splitter • Interference • All light reaches the same detector

20. |x↑> |x↓> |y↑> |x↑> |x↓> The Hardy Atom • An atom is prepared to be in the state |y↑> • It is then split by a Stern-Gerlach Magnet into |x↓> and |x↑> • The two halves of the wave function are confined into boxes • That are transparent for photons but opaque for the atoms • One of the boxes is placed on one arm of an interferometer • Such that if the atom is in that box and if the photon passes in that arm, absorption occurs with probability 1. • Two Hardy atoms can be entangled into an EPR pair

21. Time-Reversed EPR(Elitzur, Dolev & Zeilinger 2001) • Two Hardy atoms in x-spin superposition (but not entangled) • “Forbidden” detector clicks • Where did the photon come from? Ignorance begets entanglement! • The atoms are entangled (i.e. violate Bell’s Inequality) • Giving rise to EPR with the entangling event not in the past but in the future no interference interference … or better call it: RPE

22. The Bell Inequality Violations The results predicted by QM:

23. The Quantum Liar Paradox • To prove non-locality, test the two Hardy atoms for Bell Inequality • Use Spin measurement in 3 directions relative to the x-axis: 00, 300, and -300 • For 00, just inspect the two boxes (“which box” measurement) • For 300 and -300 directions, re-unite the boxes, then split according to desired direction, and finally measure position

24. The Quantum Liar Paradox • 00 direction (“which box”) measurement allows only one history for the photon

25. The Quantum Liar Paradox • 00 direction (“which box”) measurement on the left atom • But a different direction (300, -300) measurement on the right atom • Here too, there are Bell Inequality violations… • Which require a non-local effect between the left and the right atoms!

26. The Quantum Liar Paradox So, you end up with the following history: • One atom is found to have blocked the photon’s path. • Hence, it appears that it could not interact with the other atom, • and therefore should not be entangled with it. • But, by violating Bell’s inequality, its “having blocked the photon” was affected by the measurement of the other atom! Which is logically equivalent to saying…

27. THIS SENTENCE HAS NEVER BEEN WRITTEN :-)

28. The Quantum Liar Paradox,Zoller & Cirac’s system • 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

29. The Quantum Liar Paradox,Zoller & Cirac’s system • 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!

30. Non-Sequential Behavior of the Wave Function (Elitzur & Dolev, 2010): • Three Hardy atoms in x-spin superposition (but not entangled): • Photon goes through; discarding all cases where one atom absorbed the photon • “Forbidden” detector D clicks, hencesomething must have disturbed the photon • The middle atom is measured and found (56% of the cases!) to have “collapsed” into the intersecting box • All other atoms restore their original superposition! D C

31. Aharonov, Y., and Rohrlich, D. (2005) Quantum Paradoxes: Quantum Theory for the Perplexed. New York: Wiley. Properties of a Quantum System between Measurements: “Every quantum event is visited twice, once by the state vector coming from the pre-selection and then again by the vector coming backwards from the post-selection” (Aharonov, personal communication).

32. Большая Советская Энциклопедия

33. Outline • Time’s Passage: Apparent? Real? • Quantum Clues • Relativistic Clues • The Model

35. t t x x A jurisdiction overlap between SR and GR: How is spacetime formed i) near mass, and ii) at inertial motion?

36. Outline • Time’s Passage: Apparent? Real? • Quantum Clues • Relativistic Clues • The Model

37. The Assumption of Becoming Events are created anew, one after another, in spacetime, according to their causal order. At any moment in time which one perceives as “Now,” future events are not only unknown but objectively inexistent, to be created later as the Now “advances.”

38. Becoming – The Ultimate Compactification? It may make work just as well as extra space dimensions

39. The Machian Consequence Where there are no events, there is neither space nor time (Mach) If there are no future events at any “Now,” there is no spacetime in the future either. Spacetime must be “growing” in the future direction

40. A Cosmological Ring Spacetime is “preceded” and “bounded” by nothingness

41. “Time and space are necessary forms of any thought ” and of any PowerPoint slide”

42. Never spatialize time!

43. Block Universe

44. Naïve Becoming

45. Let’s Go Quantum: Quantum interaction takes place beyond the “Now,” hence outside of spacetime. “Collapse” gives rise not only to the particle in its location, but to all the points in empty space where it could have been. The spacetime zone associated with this interaction emerges only as its consequence.

46. Becoming at the quantum level

47. Special Relativity Dynamized The speed of light/gravity is more basic than space and time Because the gravitational/electromagnetic interaction precedes the relative positioning of events.

48. General Relativity Dynamized Mass gives rise not only to spacetime curvature but to “bumps” in the Now plane

49. Less Naïve Becoming

50. Consequence: The Origins of Time-Asymmetry Becoming is the master arrow of time Which creates spacetime intervals between events