Time symmetry in quantum theories and beyond

• URL: http://arxiv.org/abs/2209.07867v1
• Date: Fri, 16 Sep 2022 11:41:58 GMT
• Title: Time symmetry in quantum theories and beyond
• Authors: John H. Selby, Maria E. Stasinou, Stefano Gogioso, Bob Coecke
• Abstract summary: There is a stark tension among different formulations of quantum theory in that some are fundamentally time-symmetric and others are radically time-asymmetric. This tension is captured when thinking of physical theories as theories of processes. We show how quantum theory can be described in this language.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: There is a stark tension among different formulations of quantum theory in that some are fundamentally time-symmetric and others are radically time-asymmetric. This tension is crisply captured when thinking of physical theories as theories of processes. We review process theories and their diagrammatic representation, and show how quantum theory can be described in this language. The tension between time-symmetry and time-asymmetry is then captured by the tension between two of the key structures that are used in this framework. On the one hand, the symmetry is captured by a dagger structure, which is represented by a reflection of diagrams. On the other hand, the asymmetry is captured by a condition involving discarding which, ultimately, is responsible for the theory being compatible with relativistic causality. Next we consider three different ways in which we this tension can be resolved. The first of these is closely related to recent work of Lucien Hardy, where the tension is resolved by adding in a time reversed version of discarding together with a suitable consistency condition. The second is, to our knowledge, a new approach. Here the tension is resolved by adding in new systems which propagate backwards in time, and imposing a consistency condition to avoid running into well known time-travel paradoxes. The final approach that we explore is closely related to work of Oreshkov and Cerf, where the tension is resolved by removing the constraint associated with discarding. We show two equivalent ways in which this can be done whilst ensuring that the resulting theory still makes sensible operational predictions.

Related papers

• Super Quantum Mechanics [37.69303106863453]
  We introduce Super Quantum Mechanics (SQM) as a theory that considers states in Hilbert space subject to multiple quadratic constraints. In this case, the stationary SQM problem is a quantum inverse problem with multiple applications in machine learning and artificial intelligence.
  arXiv  Detail & Related papers  (2025-01-25T19:41:04Z)
• Fundamental limits for realising quantum processes in spacetime [1.7802147489386633]
  We derive no-go theorems for quantum experiments realisable in classical background spacetimes. Our first theorem implies that realisations of ICO processes that do not violate relativistic causality must involve the non-localization of systems in spacetime. The second theorem shows that for any such realisation of an ICO process, there exists a more fine-grained description in terms of a definite and acyclic causal order process.
  arXiv  Detail & Related papers  (2024-08-23T21:41:49Z)
• A Theory of Quantum Jumps [44.99833362998488]
  We study fluorescence and the phenomenon of quantum jumps'' in idealized models of atoms coupled to the quantized electromagnetic field. Our results amount to a derivation of the fundamental randomness in the quantum-mechanical description of microscopic systems.
  arXiv  Detail & Related papers  (2024-04-16T11:00:46Z)
• Time and event symmetry in quantum mechanics [0.0]
  We find that recent time symmetric interpretations of quantum mechanics fail to respect event symmetry. We then use this model to resolve conceptual paradoxes with time symmetric quantum mechanics within an all-at-once', atemporal picture.
  arXiv  Detail & Related papers  (2023-12-21T01:59:21Z)
• An ontological description for relativistic, massive bosons [0.0]
  Locality holds for the quantum theory, and seems to be fully obeyed also by the classical treatment. We do discuss extensively the distinction between the quantum treatment and the classical one, even though they produce exactly the same equations mathematically. It is suggested to apply this theory for real time quantum model simulations.
  arXiv  Detail & Related papers  (2023-06-16T14:53:02Z)
• Universality of critical dynamics with finite entanglement [68.8204255655161]
  We study how low-energy dynamics of quantum systems near criticality are modified by finite entanglement. Our result establishes the precise role played by entanglement in time-dependent critical phenomena.
  arXiv  Detail & Related papers  (2023-01-23T19:23:54Z)
• Entanglement, Complexity, and Causal Asymmetry in Quantum Theories [0.0]
  It is often claimed that one cannot locate a notion of causation in fundamental physical theories. I argue that this is incorrect: the ubiquitous generation of entanglement between quantum systems grounds a relevant in the dynamical evolution of quantum systems.
  arXiv  Detail & Related papers  (2022-04-14T03:41:18Z)
• Open-system approach to nonequilibrium quantum thermodynamics at arbitrary coupling [77.34726150561087]
  We develop a general theory describing the thermodynamical behavior of open quantum systems coupled to thermal baths. Our approach is based on the exact time-local quantum master equation for the reduced open system states.
  arXiv  Detail & Related papers  (2021-09-24T11:19:22Z)
• Emergence of Constructor-based Irreversibility in Quantum Systems: Theory and Experiment [0.0]
  We show that irreversibility in a universe with time-reversal-symmetric laws is compatible with quantum theory's time reversal symmetric laws. We exploit a specific model, based on the universal quantum homogeniser, realised experimentally with high-quality single-photon qubits.
  arXiv  Detail & Related papers  (2020-09-30T12:57:39Z)
• There is only one time [110.83289076967895]
  We draw a picture of physical systems that allows us to recognize what is this thing called "time" We derive the Schr"odinger equation in the first case, and the Hamilton equations of motion in the second one.
  arXiv  Detail & Related papers  (2020-06-22T09:54:46Z)
• From a quantum theory to a classical one [117.44028458220427]
  We present and discuss a formal approach for describing the quantum to classical crossover. The method was originally introduced by L. Yaffe in 1982 for tackling large-$N$ quantum field theories.
  arXiv  Detail & Related papers  (2020-04-01T09:16:38Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.