Interpreting Quantum Nonlocality As Platonic Information
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Generalised Noncommutative Geometry on Finite Groups and Hopf
J. Noncommut. Geom. 13 (2019), 1055–1116 Journal of Noncommutative Geometry DOI 10.4171/JNCG/345 © European Mathematical Society Generalised noncommutative geometry on finite groups and Hopf quivers Shahn Majid and Wen-Qing Tao Abstract. We explore the differential geometry of finite sets where the differential structure is given by a quiver rather than as more usual by a graph. In the finite group case we show that the data for such a differential calculus is described by certain Hopf quiver data as familiar in the context of path algebras. We explore a duality between geometry on the function algebra vs geometry on the group algebra, i.e. on the dual Hopf algebra, illustrated by the noncommutative Riemannian geometry of the group algebra of S3. We show how quiver geometries arise naturally in the context of quantum principal bundles. We provide a formulation of bimodule Riemannian geometry for quantum metrics on a quiver, with a fully worked example on 2 points; in the quiver case, metric data assigns matrices not real numbers to the edges of a graph. The paper builds on the general theory in our previous work [19]. Mathematics Subject Classification (2010). 81R50, 58B32, 16G20. Keywords. Hopf algebra, nonsurjective calculus, quiver, duality, finite group, bimodule connection. 1. Introduction Noncommutative differential geometry is an extension of geometry to the case where the coordinate algebra A may be noncommutative or “quantum.” The starting point is a “differential structure” on A defined as a pair .1; d/ where the space of “1-forms” 1 is an A-A-bimodule (so one can multiply by the algebra from the left or the right) and d A 1 obeys the Leibniz rule. -
The Concept of Quantum State : New Views on Old Phenomena Michel Paty
The concept of quantum state : new views on old phenomena Michel Paty To cite this version: Michel Paty. The concept of quantum state : new views on old phenomena. Ashtekar, Abhay, Cohen, Robert S., Howard, Don, Renn, Jürgen, Sarkar, Sahotra & Shimony, Abner. Revisiting the Founda- tions of Relativistic Physics : Festschrift in Honor of John Stachel, Boston Studies in the Philosophy and History of Science, Dordrecht: Kluwer Academic Publishers, p. 451-478, 2003. halshs-00189410 HAL Id: halshs-00189410 https://halshs.archives-ouvertes.fr/halshs-00189410 Submitted on 20 Nov 2007 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. « The concept of quantum state: new views on old phenomena », in Ashtekar, Abhay, Cohen, Robert S., Howard, Don, Renn, Jürgen, Sarkar, Sahotra & Shimony, Abner (eds.), Revisiting the Foundations of Relativistic Physics : Festschrift in Honor of John Stachel, Boston Studies in the Philosophy and History of Science, Dordrecht: Kluwer Academic Publishers, 451-478. , 2003 The concept of quantum state : new views on old phenomena par Michel PATY* ABSTRACT. Recent developments in the area of the knowledge of quantum systems have led to consider as physical facts statements that appeared formerly to be more related to interpretation, with free options. -
Light and Matter Diffraction from the Unified Viewpoint of Feynman's
European J of Physics Education Volume 8 Issue 2 1309-7202 Arlego & Fanaro Light and Matter Diffraction from the Unified Viewpoint of Feynman’s Sum of All Paths Marcelo Arlego* Maria de los Angeles Fanaro** Universidad Nacional del Centro de la Provincia de Buenos Aires CONICET, Argentine *[email protected] **[email protected] (Received: 05.04.2018, Accepted: 22.05.2017) Abstract In this work, we present a pedagogical strategy to describe the diffraction phenomenon based on a didactic adaptation of the Feynman’s path integrals method, which uses only high school mathematics. The advantage of our approach is that it allows to describe the diffraction in a fully quantum context, where superposition and probabilistic aspects emerge naturally. Our method is based on a time-independent formulation, which allows modelling the phenomenon in geometric terms and trajectories in real space, which is an advantage from the didactic point of view. A distinctive aspect of our work is the description of the series of transformations and didactic transpositions of the fundamental equations that give rise to a common quantum framework for light and matter. This is something that is usually masked by the common use, and that to our knowledge has not been emphasized enough in a unified way. Finally, the role of the superposition of non-classical paths and their didactic potential are briefly mentioned. Keywords: quantum mechanics, light and matter diffraction, Feynman’s Sum of all Paths, high education INTRODUCTION This work promotes the teaching of quantum mechanics at the basic level of secondary school, where the students have not the necessary mathematics to deal with canonical models that uses Schrodinger equation. -
Quantum Nondemolition Photon Detection in Circuit QED and the Quantum Zeno Effect
PHYSICAL REVIEW A 79, 052115 ͑2009͒ Quantum nondemolition photon detection in circuit QED and the quantum Zeno effect Ferdinand Helmer,1 Matteo Mariantoni,2,3 Enrique Solano,1,4 and Florian Marquardt1 1Department of Physics, Center for NanoScience, and Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, Theresienstrasse 37, D-80333 Munich, Germany 2Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, D-85748 Garching, Germany 3Physics Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany 4Departamento de Quimica Fisica, Universidad del Pais Vasco-Euskal Herriko Unibertsitatea, 48080 Bilbao, Spain ͑Received 17 December 2007; revised manuscript received 15 January 2009; published 20 May 2009͒ We analyze the detection of itinerant photons using a quantum nondemolition measurement. An important example is the dispersive detection of microwave photons in circuit quantum electrodynamics, which can be realized via the nonlinear interaction between photons inside a superconducting transmission line resonator. We show that the back action due to the continuous measurement imposes a limit on the detector efficiency in such a scheme. We illustrate this using a setup where signal photons have to enter a cavity in order to be detected dispersively. In this approach, the measurement signal is the phase shift imparted to an intense beam passing through a second cavity mode. The restrictions on the fidelity are a consequence of the quantum Zeno effect, and we discuss both analytical results and quantum trajectory simulations of the measurement process. DOI: 10.1103/PhysRevA.79.052115 PACS number͑s͒: 03.65.Ta, 03.65.Xp, 42.50.Lc I. INTRODUCTION to be already prepared in a certain state. -
Many Physicists Believe That Entanglement Is The
NEWS FEATURE SPACE. TIME. ENTANGLEMENT. n early 2009, determined to make the most annual essay contest run by the Gravity Many physicists believe of his first sabbatical from teaching, Mark Research Foundation in Wellesley, Massachu- Van Raamsdonk decided to tackle one of setts. Not only did he win first prize, but he also that entanglement is Ithe deepest mysteries in physics: the relation- got to savour a particularly satisfying irony: the the essence of quantum ship between quantum mechanics and gravity. honour included guaranteed publication in After a year of work and consultation with col- General Relativity and Gravitation. The journal PICTURES PARAMOUNT weirdness — and some now leagues, he submitted a paper on the topic to published the shorter essay1 in June 2010. suspect that it may also be the Journal of High Energy Physics. Still, the editors had good reason to be BROS. ENTERTAINMENT/ WARNER In April 2010, the journal sent him a rejec- cautious. A successful unification of quantum the essence of space-time. tion — with a referee’s report implying that mechanics and gravity has eluded physicists Van Raamsdonk, a physicist at the University of for nearly a century. Quantum mechanics gov- British Columbia in Vancouver, was a crackpot. erns the world of the small — the weird realm His next submission, to General Relativity in which an atom or particle can be in many BY RON COWEN and Gravitation, fared little better: the referee’s places at the same time, and can simultaneously report was scathing, and the journal’s editor spin both clockwise and anticlockwise. Gravity asked for a complete rewrite. -
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. -
Measurement Theories in Quantum Mechanics
Measurement Theories in Quantum Mechanics Cortland M. Setlow March 3, 2006 2 Contents 1 Introduction 1 1.1 Intent .. 1 1.2 Overview. 1 1.3 New Theories from Old 3 2 A Brief Review of Mechanics 7 2.1 Newtonian Mechanics: F = mn 8 2.1.1 Newton's Laws of Motion. 8 2.1.2 Mathematics and the Connection to Experiment 9 2.2 Hamiltonian and Lagrangian Mechanics . 10 2.2.1 Lagrangian Mechanics . 10 2.2.2 Hamiltonian Mechanics 12 2.2.3 Conclusions ....... 13 2.3 The Hamiltonian in Quantum Mechanics 14 2.4 The Lagrangian in Quantum Mechanics 14 2.5 Conclusion . .......... 15 3 The Measurement Problem 17 3.1 Introduction . 17 3.2 Quantum Mysteries. 18 i ii CONTENTS 3.2.1 Probability Rules . 18 3.2.2 Probability in Experiments: Diffraction 19 3.3 Conclusions .......... 20 3.3.1 Additional Background 20 3.3.2 Summary ..... 21 4 Solutions to Quantum Problems 23 4.1 Introduction . 23 4.2 Orthodox Theory 23 4.2.1 Measurement in the Orthodox Theory . 24 4.2.2 Criticisms of Orthodox Measurement 24 4.2.3 Conclusions ... 25 4.3 Ghirardi-Rimini-Weber . 25 4.3.1 Dynamics 26 4.3.2 Motivation. 26 4.3.3 Criticisms 28 4.4 Hidden Variables 30 4.4.1 Dynamics of Bohm's Hidden Variables Interpretation. 31 4.4.2 Introducing the Hidden Variables .... 32 4.4.3 But What About von Neumann's Proof? . 33 4.4.4 Relativity and the Quantum Potential 34 4.5 Everett's Relative State Formulation 34 4.5.1 Motivation . -
Public Request to Take Stronger Measures of Social Distancing Across the UK with Immediate Effect 14Th March 2020
Public request to take stronger measures of social distancing across the UK with immediate effect 14th March 2020 (last update: 15th March 2020, 18:25) As scientists living and working in the UK, we would like to express our concern about the course of action announced by the Government on 12th March 2020 regarding the Coronavirus outbreak. In particular, we are deeply preoccupied by the timeline of the proposed plan, which aims at delaying social distancing measures even further. The current data about the number of infections in the UK is in line with the growth curves already observed in other countries, including Italy, Spain, France, and Germany [1]. The same data suggests that the number of infected will be in the order of dozens of thousands within a few days. Under unconstrained growth, this outbreak will affect millions of people in the next few weeks. This will most probably put the NHS at serious risk of not being able to cope with the flow of patients needing intensive care, as the number of ICU beds in the UK is not larger than that available in other neighbouring countries with a similar population [2]. Going for \herd immunity" at this point does not seem a viable option, as this will put NHS at an even stronger level of stress, risking many more lives than necessary. By putting in place social distancing measures now, the growth can be slowed down dramatically, and thousands of lives can be spared. We consider the social distancing measures taken as of today as insufficient, and we believe that addi- tional and more restrictive measures should be taken immediately, as it is already happening in other countries across the world. -
A Live Alternative to Quantum Spooks
International Journal of Quantum Foundations 6 (2020) 1-8 Original Paper A live alternative to quantum spooks Huw Price1;∗ and Ken Wharton2 1. Trinity College, Cambridge CB2 1TQ, UK 2. Department of Physics and Astronomy, San José State University, San José, CA 95192-0106, USA * Author to whom correspondence should be addressed; E-mail:[email protected] Received: 14 December 2019 / Accepted: 21 December 2019 / Published: 31 December 2019 Abstract: Quantum weirdness has been in the news recently, thanks to an ingenious new experiment by a team led by Roland Hanson, at the Delft University of Technology. Much of the coverage presents the experiment as good (even conclusive) news for spooky action-at-a-distance, and bad news for local realism. We point out that this interpretation ignores an alternative, namely that the quantum world is retrocausal. We conjecture that this loophole is missed because it is confused for superdeterminism on one side, or action-at-a-distance itself on the other. We explain why it is different from these options, and why it has clear advantages, in both cases. Keywords: Quantum Entanglement; Retrocausality; Superdeterminism Quantum weirdness has been getting a lot of attention recently, thanks to a clever new experiment by a team led by Roland Hanson, at the Delft University of Technology.[1] Much of the coverage has presented the experiment as good news for spooky action-at-a-distance, and bad news for Einstein: “The most rigorous test of quantum theory ever carried out has confirmed that the ‘spooky action-at-a-distance’ that [Einstein] famously hated . -
Quantum Theory Needs No 'Interpretation'
Quantum Theory Needs No ‘Interpretation’ But ‘Theoretical Formal-Conceptual Unity’ (Or: Escaping Adán Cabello’s “Map of Madness” With the Help of David Deutsch’s Explanations) Christian de Ronde∗ Philosophy Institute Dr. A. Korn, Buenos Aires University - CONICET Engineering Institute - National University Arturo Jauretche, Argentina Federal University of Santa Catarina, Brazil. Center Leo Apostel fot Interdisciplinary Studies, Brussels Free University, Belgium Abstract In the year 2000, in a paper titled Quantum Theory Needs No ‘Interpretation’, Chris Fuchs and Asher Peres presented a series of instrumentalist arguments against the role played by ‘interpretations’ in QM. Since then —quite regardless of the publication of this paper— the number of interpretations has experienced a continuous growth constituting what Adán Cabello has characterized as a “map of madness”. In this work, we discuss the reasons behind this dangerous fragmentation in understanding and provide new arguments against the need of interpretations in QM which —opposite to those of Fuchs and Peres— are derived from a representational realist understanding of theories —grounded in the writings of Einstein, Heisenberg and Pauli. Furthermore, we will argue that there are reasons to believe that the creation of ‘interpretations’ for the theory of quanta has functioned as a trap designed by anti-realists in order to imprison realists in a labyrinth with no exit. Taking as a standpoint the critical analysis by David Deutsch to the anti-realist understanding of physics, we attempt to address the references and roles played by ‘theory’ and ‘observation’. In this respect, we will argue that the key to escape the anti-realist trap of interpretation is to recognize that —as Einstein told Heisenberg almost one century ago— it is only the theory which can tell you what can be observed. -
Black Holes and Qubits
Subnuclear Physics: Past, Present and Future Pontifical Academy of Sciences, Scripta Varia 119, Vatican City 2014 www.pas.va/content/dam/accademia/pdf/sv119/sv119-duff.pdf Black Holes and Qubits MICHAEL J. D UFF Blackett Labo ratory, Imperial C ollege London Abstract Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two. Introduction Whenever two very different areas of theoretical physics are found to share the same mathematics, it frequently leads to new insights on both sides. Here we describe how knowledge of string theory and M-theory leads to new discoveries about Quantum Information Theory (QIT) and vice-versa (Duff 2007; Kallosh and Linde 2006; Levay 2006). Bekenstein-Hawking entropy Every object, such as a star, has a critical size determined by its mass, which is called the Schwarzschild radius. A black hole is any object smaller than this. Once something falls inside the Schwarzschild radius, it can never escape. This boundary in spacetime is called the event horizon. So the classical picture of a black hole is that of a compact object whose gravitational field is so strong that nothing, not even light, can escape. Yet in 1974 Stephen Hawking showed that quantum black holes are not entirely black but may radiate energy, due to quantum mechanical effects in curved spacetime. In that case, they must possess the thermodynamic quantity called entropy. -
Lessons of Bell's Theorem
Lessons of Bell's Theorem: Nonlocality, yes; Action at a distance, not necessarily. Wayne C. Myrvold Department of Philosophy The University of Western Ontario Forthcoming in Shan Gao and Mary Bell, eds., Quantum Nonlocality and Reality { 50 Years of Bell's Theorem (Cambridge University Press) Contents 1 Introduction page 1 2 Does relativity preclude action at a distance? 2 3 Locally explicable correlations 5 4 Correlations that are not locally explicable 8 5 Bell and Local Causality 11 6 Quantum state evolution 13 7 Local beables for relativistic collapse theories 17 8 A comment on Everettian theories 19 9 Conclusion 20 10 Acknowledgments 20 11 Appendix 20 References 25 1 Introduction 1 1 Introduction Fifty years after the publication of Bell's theorem, there remains some con- troversy regarding what the theorem is telling us about quantum mechanics, and what the experimental violations of Bell inequalities are telling us about the world. This chapter represents my best attempt to be clear about what I think the lessons are. In brief: there is some sort of nonlocality inherent in any quantum theory, and, moreover, in any theory that reproduces, even approximately, the quantum probabilities for the outcomes of experiments. But not all forms of nonlocality are the same; there is a distinction to be made between action at a distance and other forms of nonlocality, and I will argue that the nonlocality needed to violate the Bell inequalities need not involve action at a distance. Furthermore, the distinction between forms of nonlocality makes a difference when it comes to compatibility with relativis- tic causal structure.