Testing Foundations of Quantum Mechanics at Different Energy Scales

1. Spooky action at distance also for neutral kaons? Testing Foundations of Quantum Mechanics at Different Energy Scales by Beatrix C. Hiesmayr University of Vienna 2SGA2746 Projects FWF-P21947N16and FWF-P23627

2. Beatrix C. Hiesmayr Very short history… 1935: Einstein-Podolsky-Rosen-PARADOX ALICE BOB The EPR reality criterion: “If without in any way disturbing a system, one can predict with certainty (i.e. with the probability equal to one) the value of a physical quantity, then there exists an element of physical reality corresponding to this physical quantity.”  Quantum Theory is not complete! ALICE BOB 1. pair 2. pair 3. pair 4. pair …

3. Very short history… 1935: Einstein-Podolsky-Rosen-PARADOX Hobby: Foundations of QM 1964: John Stuart Bell

4. What are Bell inequalities? No spooky action at distance! realism locality free will* *exerting their independence; totally randomly Local realistic theories: Quantum Mechanics: Bell’s locality hypothesis  QM probabilities may violate the inequalities! inequalities for probabilities always satisfied! Experiment has to decide!

5. Are local realistic theories ruled out? Photons: many experiments, show violations but still loopholes Various ordinary matter systems: show violations but still loopholes !Single! neutrons: show violations but tests different aspects

6. The EPR scenario 1935: Einstein-Podolsky-Rosen-PARADOX Bell state: ... spin 1/2 ... photon (polarisation) High Energy Physics ... kaons (K-mesons) ... B-meson 1998: CPLEAR collaboration, Physics Letters B 422, 339 Branching ratio depends on hydrogen density

7. What are Bell inequalities good for? • Has been proven: quantum cryptography protocols are save if a Bell inequality is violated! • Quantum Computers/Quantum Communication Complexity: Bell inequalities are necessary and sufficient conditions for quantum protocols to beat the classical ones!

8. My goal: to test Bell inequalities for Neutral Kaons • very difficult, not straightforwardly (even from theoretical point of view)! • but new physics is revealed! • since last year (2012) there is a hope of a doable experiment (with KLOE?, with FLAIR?,…?)

9. Requirements for tests LRT versus QM • Requirements for a conclusive proof of the existence of correlation stronger than those explainable by locality and realism/explainable by local resources & shared randomness: • “Active” measurements (opening the possibility for Alice and Bob to choose among alternative setups-> free choice) • “Use all information” (test the whole ensemble; decay product states are included this “additional” information cannot be ignored) Only for kaons & strangeness measurements!! was/is overlooked by many researchers !! are not “only” loopholes!

10. Bell inequality for kaons • Bertlmann & Hiesmayr,Phys. Rev. A (2001) local realistic models Violation! Kaons? NO violation!

11. Summary I If we believe in QM, then there is “spooky action at distance” also for this system at different energy scale, but there exists NO CONCLUSIVE EXPERIMENT so far. Hiesmayr, Eur. Phys. J. C (2007) A violation for observables that can be actively measured can be found, but for an initial non-maximally entangled state. Frascati, Italy Hiesmayr, Domenico, Curceanu, Gabriel, Huber, Larsson, Moskal, Eur. Phys. J. C (2012) New Bell inequality for unstable systems that is experimentally feasible and can be performed with current technology!

12. !?Nonlocality related to a symmetry violation?! 1964 Bell inequalities CP violation There exists correlations stronger than classical physics allows! world anti-world

13. CP violation (C…charge conjugations,P…parity) Experiment: 1964Christensen, Cronin, Fitch and Turlay CP violation! Leptonic charge asymmetry:

14. Why are we living in a matter dominated universe?

15. Bell inequality for kaons • Bertlmann & Hiesmayr,Phys. Rev. A (2001) local realistic models taking into account the decay property without loosing the conclusiveness Hiesmayr et al., Eur. Phys. J. C (2012) • for stable systems gives +/-2

16. Bell inequality for kaons Bell inequality Bound • for stable systems gives +/-2

17. Bell inequality for kaons  sensitive to CP violation !!! Bell inequality Bound Bell inequality Bound

18. Revealing Bell’s Nonlocality for Unstable Systems in High Energy Physics B.C. Hiesmayr Hiesmayr, Domenico, Curceanu, Gabriel, Huber, Larsson, Moskal, Eur. Phys. J. C (2012)

19. Revealing Bell’s Nonlocality for Unstable Systems in High Energy Physics Hiesmayr, Domenico, Curceanu, Gabriel, Huber, Larsson, Moskal, Eur. Phys. J. C (2012)

20. A little history… Drawn by R.A. Bertlmann to the 60th birthday of John Bell

21. What other foundations of QM can be tested? … a lot !! • The kaoniceraser: „ErasingthePastImpactingthe Future“ • Heisenbergs Uncertainty Relation, Bohr‘scomplementarityrelation, … • Test entanglement: Istheredecoherence in thesystem? (->Whatcausesdecoherence? CPT violation (stringtheory), Lorentz-Invariance, dark matter,…) • Collapse Models Aharanov & Zubairy: Science 307:875, 2005 Bramon, Garbarino, Hiesmayr , Phys. Rev. Lett. 92 (2004) offers new options ! can be tested at KLOE 2! A. Di Domenico, A. Gabriel, B. C. Hiesmayr, F. Hipp, M. Huber, G. Krizek, K. Mühlbacher, S. Radic, Ch. Spengler and L. Theussl, Found. Of Physics (2011) A. Bramon, G. Garbarino, Hiesmayr Phys. Rev. A 68 (2004). Nature: Scientific Reports: Testing Collapse Models with Neutrinos, Mesons and Chiral Molecules

22. Summary Testing Foundations of QM at all energy scales has started! Higher energies reveal different aspects and new physics! To obtain a full picture of entanglement and to reveal its role in our universe all systems have to be considered! Accelerator experiments can add to our understanding of quantum foundations! … experiments ? KLOE, ELENA, FLAIR

23. Thank you for Your attention! The Quantum-Particle Group www.quantumparticlegroup.at

24. Why do we see no macroscopic superpositions? Is there a border between a quantum and classical world? And if where is it? • SCHRÖDINGER EQUATION: linear, deterministic, reversible • WAVE PACKET REDUCTION (measurement): nonlinear, stochastic, irreversible One solution: COLLAPSE MODELS (Ghirardi-Rimini-Weber,1986) Consequence: QM would be not fundamental  assumes a random field filling space  Origin? Gravitation (Penrose), Dark matter/energy,…?

25. Can the collapse be measured for flavor oscillations? Donaldi, Bassi, Curceanu, DiDomenico, Hiesmayr, arXiv:1207.6000 Bahrami, Donaldi, Ferialdi, Bassi, Curceanu, DiDomenico, Hiesmayr, submitted After a long and cumbersome computation… strength of the collapse correlation length Can this be measured?? Neutrinos?

26. This Wednesday and Thursday

27. An experiment for kaons • How good do these two data points verify the quantum mechanical interference term? • Is the Schrödinger-Furry hypothesis really ruled out? • Is there decoherence in the system? Loss of entanglement? Traces of quantum gravity, CPT violations,…

28. Spontaneous factorization of the wave function Schrödinger-Furry Hypothesis: 50% 50% Observable: CPLEAR-experiment (1998): Bertlmann, Grimus and Hiesmayr, Phys. Rev. D, 60, 114032 (1999)

29. Spontaneous factorization of the wave function 50%50% Schrödinger-Furry Hypothesis : CPLEAR-experiment (1998): Bertlmann, Grimus and Hiesmayr, Phys. Rev. D, 60, 114032 (1999)

30. Testing entanglement/decoherence Bertlmann, Grimus, Hiesmayr, Phys.Rev. D (1999) Different observable! KLOE Coll., Phys. Lett. B (2006) DiDomenico (2009) But z(t)=1-e-lt? B-mesons: PhD, Gerald Richter, HEPHY 2007 A.Go, BELLE, PRL (2008) B.D. Yabsley (2008) arXiv:0810.1822 (D-mesons)

31. “Erasing the past and impacting the future”The quantum eraser 1801 Thomas Young: Photons interfere! Interference lost because photon watched (gain which way info)! 1982 Drühl & Scully: Erasing the which way info brings interference back! No wonder Einstein would be confused!

32. Bell inequality for unstable systems Assumption: time evolution (exponential decay) of single kaons is correctly described by QM Experiment: Control over single and joint probabilities ! • for stable systems gives +/-2 Frascati, Italy

33. Crash course on neutral kaons: Strangeness: Mass-eigenstates: „A kaon is a kind of double slit“ Bramon, Garbarino, H., PRA (2004) Kaon in time: short-lived state long-lived state Feynman diagram

34. Univ. of Vienna 2011, Beatrix C. Hiesmayr Loopholes “Detection Loophole”: if not all pairs are measured or if some are misidentified due to imperfections of the detectors, Nature could still be local since some information is missing (“fair sampling assumption”). not closed! …but full control over single and joint probabilities! “Locality Loophole”: measurements of Alice and Bob have to be space-like separated, thus avoiding any possible exchange of subluminal signals about the measurement choices of Alice and Bob Could be closed with enough money… Advantages: one knows essentially with 100% probability that in case a neutral kaon is reconstructed it can only come from an entangled pair. In addition, on average only one entangled pair is generated per event.

35. Generalized Bell inequality for kaons local realistic theories II. Vary in time: Violation! Hiesmayr, Eur. Phys. J. C (2007) Kaons? Violation! But too small ..