Quantum Nonlocality
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Arxiv:2002.00255V3 [Quant-Ph] 13 Feb 2021 Lem (BVP)
A Path Integral approach to Quantum Fluid Dynamics Sagnik Ghosh Indian Institute of Science Education and Research, Pune-411008, India Swapan K Ghosh UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina, Santacruz, Mumbai-400098, India ∗ (Dated: February 16, 2021) In this work we develop an alternative approach for solution of Quantum Trajectories using the Path Integral method. The state-of-the-art technique in the field is to solve a set of non-linear, coupled partial differential equations (PDEs) simultaneously. We opt for a fundamentally different route. We first derive a general closed form expression for the Path Integral propagator valid for any general potential as a functional of the corresponding classical path. The method is exact and is applicable in many dimensions as well as multi-particle cases. This, then, is used to compute the Quantum Potential (QP), which, in turn, can generate the Quantum Trajectories. For cases, where closed form solution is not possible, the problem is formally boiled down to solving the classical path as a boundary value problem. The work formally bridges the Path Integral approach with Quantum Fluid Dynamics. As a model application to illustrate the method, we work out a toy model viz. the double-well potential, where the boundary value problem for the classical path has been computed perturbatively, but the Quantum part is left exact. Using this we delve into seeking insight in one of the long standing debates with regard to Quantum Tunneling. Keywords: Path Integral, Quantum Fluid Dynamics, Analytical Solution, Quantum Potential, Quantum Tunneling, Quantum Trajectories Submitted to: J. -
Simulation of the Bell Inequality Violation Based on Quantum Steering Concept Mohsen Ruzbehani
www.nature.com/scientificreports OPEN Simulation of the Bell inequality violation based on quantum steering concept Mohsen Ruzbehani Violation of Bell’s inequality in experiments shows that predictions of local realistic models disagree with those of quantum mechanics. However, despite the quantum mechanics formalism, there are debates on how does it happen in nature. In this paper by use of a model of polarizers that obeys the Malus’ law and quantum steering concept, i.e. superluminal infuence of the states of entangled pairs to each other, simulation of phenomena is presented. The given model, as it is intended to be, is extremely simple without using mathematical formalism of quantum mechanics. However, the result completely agrees with prediction of quantum mechanics. Although it may seem trivial, this model can be applied to simulate the behavior of other not easy to analytically evaluate efects, such as defciency of detectors and polarizers, diferent value of photons in each run and so on. For example, it is demonstrated, when detector efciency is 83% the S factor of CHSH inequality will be 2, which completely agrees with famous detector efciency limit calculated analytically. Also, it is shown in one-channel polarizers the polarization of absorbed photons, should change to the perpendicular of polarizer angle, at very end, to have perfect violation of the Bell inequality (2 √2 ) otherwise maximum violation will be limited to (1.5 √2). More than a half-century afer celebrated Bell inequality 1, nonlocality is almost totally accepted concept which has been proved by numerous experiments. Although there is no doubt about validity of the mathematical model proposed by Bell to examine the principle of the locality, it is comprehended that Bell’s inequality in its original form is not testable. -
Violation of Bell Inequalities: Mapping the Conceptual Implications
International Journal of Quantum Foundations 7 (2021) 47-78 Original Paper Violation of Bell Inequalities: Mapping the Conceptual Implications Brian Drummond Edinburgh, Scotland. E-mail: [email protected] Received: 10 April 2021 / Accepted: 14 June 2021 / Published: 30 June 2021 Abstract: This short article concentrates on the conceptual aspects of the violation of Bell inequalities, and acts as a map to the 265 cited references. The article outlines (a) relevant characteristics of quantum mechanics, such as statistical balance and entanglement, (b) the thinking that led to the derivation of the original Bell inequality, and (c) the range of claimed implications, including realism, locality and others which attract less attention. The main conclusion is that violation of Bell inequalities appears to have some implications for the nature of physical reality, but that none of these are definite. The violations constrain possible prequantum (underlying) theories, but do not rule out the possibility that such theories might reconcile at least one understanding of locality and realism to quantum mechanical predictions. Violation might reflect, at least partly, failure to acknowledge the contextuality of quantum mechanics, or that data from different probability spaces have been inappropriately combined. Many claims that there are definite implications reflect one or more of (i) imprecise non-mathematical language, (ii) assumptions inappropriate in quantum mechanics, (iii) inadequate treatment of measurement statistics and (iv) underlying philosophical assumptions. Keywords: Bell inequalities; statistical balance; entanglement; realism; locality; prequantum theories; contextuality; probability space; conceptual; philosophical International Journal of Quantum Foundations 7 (2021) 48 1. Introduction and Overview (Area Mapped and Mapping Methods) Concepts are an important part of physics [1, § 2][2][3, § 1.2][4, § 1][5, p. -
Quantum Nonlocality Explained
Quantum Nonlocality Explained Ulrich Mohrhoff Sri Aurobindo International Centre of Education Pondicherry 605002 India [email protected] Abstract Quantum theory's violation of remote outcome independence is as- sessed in the context of a novel interpretation of the theory, in which the unavoidable distinction between the classical and quantum domains is understood as a distinction between the manifested world and its manifestation. 1 Preliminaries There are at least nine formulations of quantum mechanics [1], among them Heisenberg's matrix formulation, Schr¨odinger'swave-function formu- lation, Feynman's path-integral formulation, Wigner's phase-space formula- tion, and the density-matrix formulation. The idiosyncracies of these forma- tions have much in common with the inertial reference frames of relativistic physics: anything that is not invariant under Lorentz transformations is a feature of whichever language we use to describe the physical world rather than an objective feature of the physical world. By the same token, any- thing that depends on the particular formulation of quantum mechanics is a feature of whichever mathematical tool we use to calculate the values of observables or the probabilities of measurement outcomes rather than an objective feature of the physical world. That said, when it comes to addressing specific questions, some formu- lations are obviously more suitable than others. As Styer et al. [1] wrote, The ever-popular wavefunction formulation is standard for prob- lem solving, but leaves the conceptual misimpression that [the] wavefunction is a physical entity rather than a mathematical tool. The path integral formulation is physically appealing and 1 generalizes readily beyond the domain of nonrelativistic quan- tum mechanics, but is laborious in most standard applications. -
How the Many Worlds Interpretation Brings Common Sense to Paradoxical Quantum Experiments
How the Many Worlds Interpretation brings Common Sense to Paradoxical Quantum Experiments Kelvin J. McQueen and Lev Vaidman The many worlds interpretation of quantum mechanics (MWI) states that the world we live in is just one among many parallel worlds. It is widely believed that because of this commitment to parallel worlds, the MWI violates common sense. Some go so far as to reject the MWI on this basis. This is despite its myriad of advantages to physics (e.g. consistency with relativity theory, mathematical simplicity, realism, determinism, etc.). Here, we make the case that common sense in fact favors the MWI. We argue that causal explanations are commonsensical only when they are local causal explanations. We present several quantum mechanical experiments that seem to exhibit nonlocal “action at a distance”. Under the assumption that only one world exists, these experiments seem immune to local causal explanation. However, we show that the MWI, by taking all worlds together, can provide local causal explanations of the experiments. The MWI therefore restores common sense to physical explanation. 1. Introduction The purpose of explanation is to help us understand why things happen as they do. Typically, one explains an event by citing the causes of that event. For example, to explain why the window broke, one might cite the throwing of a stone. A particularly compelling and natural type of causal explanation is local causal explanation. In a local causal explanation there is spatiotemporal continuity between the cause and the explained effect. For example, the thrown stone explains the broken window in part because the stone traces out a continuous trajectory from the stone-thrower’s hand to the window. -
Cosmic Bell Test Using Random Measurement Settings from High-Redshift Quasars
PHYSICAL REVIEW LETTERS 121, 080403 (2018) Editors' Suggestion Cosmic Bell Test Using Random Measurement Settings from High-Redshift Quasars Dominik Rauch,1,2,* Johannes Handsteiner,1,2 Armin Hochrainer,1,2 Jason Gallicchio,3 Andrew S. Friedman,4 Calvin Leung,1,2,3,5 Bo Liu,6 Lukas Bulla,1,2 Sebastian Ecker,1,2 Fabian Steinlechner,1,2 Rupert Ursin,1,2 Beili Hu,3 David Leon,4 Chris Benn,7 Adriano Ghedina,8 Massimo Cecconi,8 Alan H. Guth,5 † ‡ David I. Kaiser,5, Thomas Scheidl,1,2 and Anton Zeilinger1,2, 1Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria 2Vienna Center for Quantum Science & Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria 3Department of Physics, Harvey Mudd College, Claremont, California 91711, USA 4Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, California 92093, USA 5Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 6School of Computer, NUDT, 410073 Changsha, China 7Isaac Newton Group, Apartado 321, 38700 Santa Cruz de La Palma, Spain 8Fundación Galileo Galilei—INAF, 38712 Breña Baja, Spain (Received 5 April 2018; revised manuscript received 14 June 2018; published 20 August 2018) In this Letter, we present a cosmic Bell experiment with polarization-entangled photons, in which measurement settings were determined based on real-time measurements of the wavelength of photons from high-redshift quasars, whose light was emitted billions of years ago; the experiment simultaneously ensures locality. Assuming fair sampling for all detected photons and that the wavelength of the quasar photons had not been selectively altered or previewed between emission and detection, we observe statistically significant violation of Bell’s inequality by 9.3 standard deviations, corresponding to an estimated p value of ≲7.4 × 10−21. -
Quantum Nonlocality As an Axiom
Foundations of Physics, Vol. 24, No. 3, 1994 Quantum Nonlocality as an Axiom Sandu Popescu t and Daniel Rohrlich 2 Received July 2, 1993: revised July 19, 1993 In the conventional approach to quantum mechanics, &determinism is an axiom and nonlocality is a theorem. We consider inverting the logical order, mak#1g nonlocality an axiom and indeterminism a theorem. Nonlocal "superquantum" correlations, preserving relativistic causality, can violate the CHSH inequality more strongly than any quantum correlations. What is the quantum principle? J. Wheeler named it the "Merlin principle" after the legendary magician who, when pursued, could change his form again and again. The more we pursue the quantum principle, the more it changes: from discreteness, to indeterminism, to sums over paths, to many worlds, and so on. By comparison, the relativity principle is easy to grasp. Relativity theory and quantum theory underlie all of physics, but we do not always know how to reconcile them. Here, we take nonlocality as the quantum principle, and we ask what nonlocality and relativistic causality together imply. It is a pleasure to dedicate this paper to Professor Fritz Rohrlich, who has contributed much to the juncture of quantum theory and relativity theory, including its most spectacular success, quantum electrodynamics, and who has written both on quantum paradoxes tll and the logical structure of physical theory, t2~ Bell t31 proved that some predictions of quantum mechanics cannot be reproduced by any theory of local physical variables. Although Bell worked within nonrelativistic quantum theory, the definition of local variable is relativistic: a local variable can be influenced only by events in its back- ward light cone, not by events outside, and can influence events in its i Universit6 Libre de Bruxelles, Campus Plaine, C.P. -
Quantum Nonlocality Does Not Exist
Quantum nonlocality does not exist Frank J. Tipler1 Department of Mathematics, Tulane University, New Orleans, LA 70118 Edited* by John P. Perdew, Temple University, Philadelphia, PA, and approved June 2, 2014 (received for review December 30, 2013) Quantum nonlocality is shown to be an artifact of the Copenhagen instantaneously the spin of particle 2 would be fixed in the op- interpretation, in which each observed quantity has exactly one posite direction to that of particle 1—if we assume that [2] col- value at any instant. In reality, all physical systems obey quantum lapses at the instant we measure the spin of particle 1. The mechanics, which obeys no such rule. Locality is restored if observed purported mystery of quantum nonlocality lies in trying to un- and observer are both assumed to obey quantum mechanics, as in derstand how particle 2 changes—instantaneously—in re- the many-worlds interpretation (MWI). Using the MWI, I show that sponse to what has happened in the location of particle 1. the quantum side of Bell’s inequality, generally believed nonlocal, There is no mystery. There is no quantum nonlocality. Particle is really due to a series of three measurements (not two as in the 2 does not know what has happened to particle 1 when its spin is standard, oversimplified analysis), all three of which have only measured. State transitions are entirely local in quantum me- local effects. Thus, experiments confirming “nonlocality” are actu- chanics. All these statements are true because quantum me- ally confirming the MWI. The mistaken interpretation of nonlocal- chanics tells us that the wave function does not collapse when ity experiments depends crucially on a question-begging version the state of a system is measured. -
Astronomical Random Numbers for Quantum Foundations Experiments
Astronomical random numbers for quantum foundations experiments The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Leung, Calvin et al. "Astronomical random numbers for quantum foundations experiments." Physical Review A 97, 4 (April 2018): 042120 As Published http://dx.doi.org/10.1103/PhysRevA.97.042120 Publisher American Physical Society Version Final published version Citable link http://hdl.handle.net/1721.1/115234 Terms of Use Creative Commons Attribution Detailed Terms http://creativecommons.org/licenses/by/3.0 PHYSICAL REVIEW A 97, 042120 (2018) Featured in Physics Astronomical random numbers for quantum foundations experiments Calvin Leung,1,* Amy Brown,1,† Hien Nguyen,2,‡ Andrew S. Friedman,3,§ David I. Kaiser,4,¶ and Jason Gallicchio1,** 1Harvey Mudd College, Claremont, California 91711, USA 2NASA Jet Propulsion Laboratory, Pasadena, California 91109, USA 3University of California, San Diego, La Jolla, California 92093, USA 4Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA (Received 7 June 2017; published 24 April 2018) Photons from distant astronomical sources can be used as a classical source of randomness to improve fundamental tests of quantum nonlocality, wave-particle duality, and local realism through Bell’s inequality and delayed-choice quantum eraser tests inspired by Wheeler’s cosmic-scale Mach-Zehnder interferometer gedanken experiment. Such sources of random numbers may also be useful for information-theoretic applications such as key distribution for quantum cryptography. Building on the design of an astronomical random number generator developed for the recent cosmic Bell experiment [Handsteiner et al. Phys. Rev. Lett. 118, 060401 (2017)], in this paper we report on the design and characterization of a device that, with 20-nanosecond latency, outputs a bit based on whether the wavelength of an incoming photon is greater than or less than ≈700 nm. -
Lev VAIDMAN Date & Place of Birth
Name: Lev VAIDMAN Date & Place of Birth: 4 Sept 1955, Leningrad, Russia Date of arrival to Israel: 24 Sept 1973 Israeli Military Service: 10.12.77 { 10.03.80, officer of the IDF Marital Status: Married, 2 children A. Education 1972-1973 Leningrad University Physics 1973-1974 Ben-Gurion University Physics 1974-1976 Hebrew University Physics & Mathematics B.Sc. 1976 1980-1982 Weizmann Institute Physics M.Sc. 1982 1982-1987 Tel-Aviv University Physics Ph.D. 1987 Title of Master's thesis: Nonperturbative Sum Rules in Quantum Chromo-Dynamics Name of Supervisor: Prof. Hector Rubinstein Title of Doctoral Dissertation: The Problem of Measurement in Relativistic Quantum Theory Name of Supervisor: Prof. Yakir Aharonov B. Academic and professional experience 2005 - present U. of Tel-Aviv Full Professor 1998-2005 U. of Tel-Aviv Associate Professor 2000-2001 Centre for Quantum Comp., Oxford U-ty Visiting Professor 1995 - 1998 U. of Tel-Aviv Senior Lecturer 1998 April -June Institute of Advanced Studies, Jerusalem Visiting Professor 1996 July -August ITP, U. of California, Santa-Barbara Visiting Professor 1996 February-March Inst. of Exp. Physics, U. of Innsbruck Visiting Professor 1990 - 1995 U. of Tel-Aviv Senior Research Associate 1987 - 1990 U. of South Carolina Assistant Visiting Professor 1986 - 1987 U. of Tel-Aviv Senior Teaching Assistant 1 C. Active participation in scientific meetings. 1985 Microphysical Reality and Quantum Formalism, Urbino, Italy. 1986 New Techniques and Ideas in Quantum Measurements Theory, New-York. 1987 Frontiers of the Philosophy of Quantum Mechanics, Philadelphia. 1988 Bell's Theorem, Quantum Theory and Conceptions of the Universe, Fairfax, MD. -
Nonlocality As an Axiom for Quantum Theory*
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server NONLOCALITY AS AN AXIOM FOR QUANTUM THEORY* Daniel Rohrlich and Sandu Pop escu School of Physics and Astronomy, Tel-Aviv University Ramat-Aviv, Tel-Aviv 69978 Israel ABSTRACT Quantum mechanics and relativistic causality together imply nonlo cality: nonlo- cal correlations (that violate the CHSH inequality) and nonlo cal equations of motion (the Aharonov-Bohm e ect). Can weinvert the logical order? We consider a conjecture that nonlo cality and relativistic causality together imply quantum mechanics. We show that correlations preserving relativistic causality can violate the CHSH inequality more strongly than quantum correlations. Also, we describ e nonlo cal equations of motion, preserving rel- ativistic causality, that do not arise in quantum mechanics. In these nonlo cal equations of motion, an exp erimenter \jams" nonlo cal correlations b etween quantum systems. 1. INTRODUCTION Two asp ects of quantum nonlo cality are nonlo cal correlations and nonlo cal equations of motion. Nonlo cal correlations arise in settings such as the one discussed by Einstein, 1 2 Po dolsky and Rosen . As Bell showed (and Asp ect has reviewed in his lecture here) no 3 theory of lo cal variables can repro duce these correlations. The Aharonov-Bohm e ect is also nonlo cal in that an electromagnetic eld in uences an electron in a region where the eld vanishes. The eld induces a relative phase b etween two sets of paths available to an electron, displacing the interference pattern b etween the two sets of paths. -
Bacciagaluppi CV
Guido Bacciagaluppi: Curriculum Vitae and List of Publications 1 December 2020 Born Milan (Italy), 24 August 1965. Italian citizen. Freudenthal Instituut Postbus 85.170 3508 AD Utrecht The Netherlands Email: [email protected] Tel.: +31 (0)30 253 5621 Fax: +31 (0)30 253 7494 Web: https://www.uu.nl/staff/GBacciagaluppi/Profile https://www.uu.nl/staff/GBacciagaluppi/Research https://www.uu.nl/staff/GBacciagaluppi/Teaching Research interests My main field of research is the philosophy of physics, in particular the philosophy of quantum theory, where I have worked on a variety of approaches, including modal interpretations (for my PhD), stochastic mechanics, Everett theory, de Broglie-Bohm pilot-wave theory and spontaneous collapse theories, with a special interest in the theory of decoherence. Other special interests include time (a)symmetry, the philosophy of probability, issues in the philosophy of logic, and the topics of emergence, causation, and empiricism. I also work on the history of quantum theory and have co-authored three books on the topic, including a widely admired monograph on the 1927 Solvay conference, and I am a contributor to the recent revival of interest in the figure and work of Grete Hermann. Present positions Academic: • Utrecht University: Associate Professor (UHD1, scale 14), Freudenthal Institute, Departement of Mathematics, Faculty of Science, and Descartes Centre for the History and Philosophy of the Sciences and the Humanities, since September 2015. • SPHERE (CNRS, Paris 7, Paris 1), Paris: Associate Member since April 2015. • Foundational Questions Institute (http://fqxi.org/): Member since February 2015. • Institut d’Histoire et de Philosophie des Sciences et des Techniques (CNRS, Paris 1, ENS), Paris: Associate Member since January 2007.