Real-space Bell inequalities in de Sitter

• URL: http://arxiv.org/abs/2203.03505v2
• Date: Tue, 26 Jul 2022 19:14:03 GMT
• Title: Real-space Bell inequalities in de Sitter
• Authors: Lloren\c{c} Espinosa-Portal\'es, Vincent Vennin
• Abstract summary: We show how Bell operators can be constructed for quantum fields in real space. We then apply our formalism to a scalar field in de-Sitter space-time.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Bell-inequality violations reveal the presence of quantum correlations between two particles that have interacted and then separated. Their generalisation to quantum fields is necessary to study a number of field-theoretic setups, such as cosmological density fluctuations. In this work, we show how Bell operators can be constructed for quantum fields in real space, and for Gaussian states we compute their expectation value in terms of the field power spectra. We then apply our formalism to a scalar field in de-Sitter space-time. We find that, in spite of the tremendous production of entangled particles with opposite wave momenta on large scales, Bell inequalities are not violated in real space. The reason is that, when considering measurements of a field at two distinct locations in real space, one implicitly traces over the configuration of the field at every other location, leading to a mixed bipartite system. This "effective decoherence" effect is responsible for the erasure of quantum features, and casts some doubts on our ability to reveal the quantum origin of cosmological structures. We finally discuss these results in the light of quantum discord.

Related papers

• A computational test of quantum contextuality, and even simpler proofs of quantumness [43.25018099464869]
  We show that an arbitrary contextuality game can be compiled into an operational "test of contextuality" involving a single quantum device. Our work can be seen as using cryptography to enforce spatial separation within subsystems of a single quantum device.
  arXiv  Detail & Related papers  (2024-05-10T19:30:23Z)
• Embezzling entanglement from quantum fields [41.94295877935867]
  Embezzlement of entanglement refers to the counterintuitive possibility of extracting entangled quantum states from a reference state of an auxiliary system. We uncover a deep connection between the operational task of embezzling entanglement and the mathematical classification of von Neumann algebras.
  arXiv  Detail & Related papers  (2024-01-14T13:58:32Z)
• Insights into Quantum Contextuality and Bell Nonclassicality: A Study on Random Pure Two-Qubit Systems [0.0]
  We explore the relationship between Kochen-Specker quantum contextuality and Bell-nonclassicality for ensembles of two-qubit pure states. We present a comparative analysis showing that the violation of a noncontextuality inequality on a given quantum state reverberates on the Bell-nonclassicality of the considered state.
  arXiv  Detail & Related papers  (2023-10-13T12:14:11Z)
• (Almost-)Quantum Bell Inequalities and Device-Independent Applications [3.7482527016282963]
  We present families of (almost)quantum Bell inequalities and highlight three foundational and DI applications. We derive quantum Bell inequalities that show a separation of the quantum boundary from certain portions of the no-signaling boundary of dimension up to 4k-8. We provide the most precise characterization of the quantum boundary known so far.
  arXiv  Detail & Related papers  (2023-09-12T15:13:02Z)
• A vertical gate-defined double quantum dot in a strained germanium double quantum well [48.7576911714538]
  Gate-defined quantum dots in silicon-germanium heterostructures have become a compelling platform for quantum computation and simulation. We demonstrate the operation of a gate-defined vertical double quantum dot in a strained germanium double quantum well. We discuss challenges and opportunities and outline potential applications in quantum computing and quantum simulation.
  arXiv  Detail & Related papers  (2023-05-23T13:42:36Z)
• Bound state of distant photons in waveguide quantum electrodynamics [137.6408511310322]
  Quantum correlations between distant particles remain enigmatic since the birth of quantum mechanics. We predict a novel kind of bound quantum state in the simplest one-dimensional setup of two interacting particles in a box. Such states could be realized in the waveguide quantum electrodynamics platform.
  arXiv  Detail & Related papers  (2023-03-17T09:27:02Z)
• Bell inequalities with overlapping measurements [52.81011822909395]
  We study Bell inequalities where measurements of different parties can have overlap. This allows to accommodate problems in quantum information. The scenarios considered show an interesting behaviour with respect to Hilbert space dimension, overlap, and symmetry.
  arXiv  Detail & Related papers  (2023-03-03T18:11:05Z)
• Entanglement measures for two-particle quantum histories [0.0]
  We prove that bipartite quantum histories are entangled if and only if the Schmidt rank of this matrix is larger than 1. We then illustrate the non-classical nature of entangled histories with the use of Hardy's overlapping interferometers.
  arXiv  Detail & Related papers  (2022-12-14T20:48:36Z)
• Quantum superpositions of Minkowski spacetime [0.0]
  "Spacetime superpositions" are quantum superpositions of different spacetimes not related by a global coordinate transformation. We consider the quantum-gravitational effects produced by superpositions of periodically identified Minkowski spacetime. We show that the detector's response exhibits discontinuous resonances at rational ratios of the superposed periodic length scale.
  arXiv  Detail & Related papers  (2022-08-25T13:31:05Z)
• Schr\"odinger's cat for de Sitter spacetime [0.0]
  We provide a new phenomenological description for the response of quantum probes on a spacetime manifold in quantum superpositions. Applying this approach to static de Sitter space, we discover scenarios in which the effects produced by the quantum spacetime are operationally indistinguishable from those induced by superpositions of Rindler trajectories in Minkowski spacetime. The distinguishability of such quantum spacetimes from superpositions of trajectories in flat space reduces to the equivalence or non-equivalence of the field correlations between the superposed amplitudes.
  arXiv  Detail & Related papers  (2020-12-18T02:54:35Z)
• Exploring 2D synthetic quantum Hall physics with a quasi-periodically driven qubit [58.720142291102135]
  Quasi-periodically driven quantum systems are predicted to exhibit quantized topological properties. We experimentally study a synthetic quantum Hall effect with a two-tone drive.
  arXiv  Detail & Related papers  (2020-04-07T15:00:41Z)

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.