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We discuss the various manifestations of quantum decoherence in the forms of dephasing, entanglement with the environment, and revelation of "which-path" information. As a specific example, we consider an electron interference experiment.…

Quantum Physics · Physics 2015-05-13 Jen-Tsung Hsiang , L. H. Ford

Decoherence is the phenomenon of non-unitary dynamics that arises as a consequence of coupling between a system and its environment. It has important harmful implications for quantum information processing, and various solutions to the…

Quantum Physics · Physics 2022-09-21 Daniel A. Lidar , K. Birgitta Whaley

Inflationary cosmological perturbations of quantum-mechanical origin generically interact with all degrees of freedom present in the early Universe. Therefore, they must be viewed as an open quantum system in interaction with an…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Jerome Martin , Vincent Vennin

Consistency of the unconventional view of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom requires that Coleman-De Luccia tunneling rates to vacua with negative cosmological constant should be…

High Energy Physics - Theory · Physics 2016-07-07 José R. Espinosa , Jean-François Fortin , Maxime Trépanier

In light of the recent swampland conjectures, we explore quantum cosmology and eternal inflation beyond the slow roll regime. We consider a model of a closed universe with a scalar field $\phi$ in the framework of tunneling approach to…

General Relativity and Quantum Cosmology · Physics 2023-04-19 Georgios Fanaras , Alexander Vilenkin

We present a decoherence-based interpretation for the quantum Zeno effect (QZE) where measurements are dynamically treated as dispersive couplings of the measured system to the apparatus, rather than the von Neumann's projections. It is…

Quantum Physics · Physics 2012-04-13 D. Z. Xu , Q. Ai , C. P. Sun

We consider the superposition of two semiclassical solutions of the Wheeler-DeWitt equation for a de Sitter universe, describing a quantized scalar vacuum propagating in a universe that is contracting in one case and expanding in the other,…

General Relativity and Quantum Cosmology · Physics 2019-01-11 Marcello Rotondo , Yasusada Nambu

We study the dynamics of a quantum particle in a constricted two-dimensional channel and analyze how the onset of quantum corrections impacts the (semi-)classical high-temperature behaviour, as temperature is lowered. We characterize both…

Quantum Physics · Physics 2025-05-08 Paolo Malgaretti , Francesco Petiziol , Alexander Schnell

The tunneling probability for a system modelling macroscopic quantum tunneling is computed. We consider an open quantum system with one degree of freedom consisting of a particle trapped in a cubic potential interacting with an environment…

Quantum Physics · Physics 2007-05-23 Esteban Calzetta , Enric Verdaguer

We study the dynamics of a Bose-Einstein condensate in a double-well potential in the mean-field approximation. Decoherence effects are considered by analyzing the couplings of the condensate to environments. Two kinds of coupling are taken…

Quantum Physics · Physics 2015-05-13 W. Wang , L. B. Fu , X. X. Yi

The evolution of the quantum wave packet describing an atom trapped in the surface-tip junction of the scanning tunneling microscope is investigated by using the time-dependent Schroedinger equation, and by a quasi-classical Hamiltonian…

Quantum Physics · Physics 2008-02-21 M. Grigorescu

We study the decoherence process for an open quantum system which is classically chaotic (a quartic double well with harmonic driving coupled to a sea of harmonic oscillators). We analyze the time dependence of the rate of entropy…

Quantum Physics · Physics 2009-11-07 Diana Monteoliva , Juan Pablo Paz

Ultracold atoms provide an ideal system for the realization of quantum technologies, but also for the study of fundamental physical questions such as the emergence of decoherence and classicality in quantum many-body systems. Here, we study…

Quantum Physics · Physics 2015-03-13 Holger Hennig , Dirk Witthaut , David K. Campbell

Decoherence-free subspaces allow for the preparation of coherent and entangled qubits for quantum computing. Decoherence can be dramatically reduced, yet dissipation is an integral part of the scheme in generating stable qubits and…

Quantum Physics · Physics 2009-11-07 Ben Tregenna , Almut Beige , Peter L. Knight

Carpet-type structures constitute an ideal laboratory to study and analyze the robustness of the interference process that underlies this phenomenon against the harmful effects of decoherence. Here, without losing any generality, for…

Quantum Physics · Physics 2021-06-14 E. Honrubia , A. S. Sanz

A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The…

High Energy Physics - Theory · Physics 2007-05-23 Stephon Alexander , Manasse Mbonye , John Moffat

We compute the rate with which super-Hubble cosmological fluctuations are decohered during inflation, by their gravitational interactions with unobserved shorter-wavelength scalar and tensor modes. We do so using Open Effective Field Theory…

High Energy Physics - Theory · Physics 2023-07-12 C. P. Burgess , R. Holman , Greg Kaplanek , Jerome Martin , Vincent Vennin

Density contrasts in the universe are governed by scalar cosmological perturbations which, when expressed in terms of gauge-invariant variables, contain a classical component from scalar metric perturbations and a quantum component from…

General Relativity and Quantum Cosmology · Physics 2022-01-11 Jen-Tsung Hsiang , Bei-Lok Hu

This article analyzes the decoherence induced on a single qubit by the interaction with a spin chain with nontrivial internal dynamics (XY-type interactions). The aim of the paper is to study the existence and properties of the so-called…

Quantum Physics · Physics 2008-03-31 Cecilia Cormick , Juan Pablo Paz

Phantom scalar theories are widely considered in cosmology, but rarely at the quantum level, where they give rise to negative-energy ghost particles. These cause decay of the vacuum into gravitons and photons, violating observational…

High Energy Physics - Phenomenology · Physics 2023-11-07 James M. Cline , Matteo Puel , Takashi Toma , Qiu Shi Wang