Quantum Features of Macroscopic Fields: Entropy and Dynamics

Macroscopic fields such as electromagnetic, magnetohydrodynamic, acoustic or gravitational waves are usually described by classical wave equations with possible additional damping terms and coherent sources. The aim of this paper is to develop a complete macroscopic formalism including random/therma...

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Main Author: Robert Alicki
Format: Article
Language:English
Published: MDPI AG 2019-07-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/21/7/705
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author Robert Alicki
author_facet Robert Alicki
author_sort Robert Alicki
collection DOAJ
description Macroscopic fields such as electromagnetic, magnetohydrodynamic, acoustic or gravitational waves are usually described by classical wave equations with possible additional damping terms and coherent sources. The aim of this paper is to develop a complete macroscopic formalism including random/thermal sources, dissipation and random scattering of waves by environment. The proposed reduced state of the field combines averaged field with the two-point correlation function called single-particle density matrix. The evolution equation for the reduced state of the field is obtained by reduction of the generalized quasi-free dynamical semigroups describing irreversible evolution of bosonic quantum field and the definition of entropy for the reduced state of the field follows from the von Neumann entropy of quantum field states. The presented formalism can be applied, for example, to superradiance phenomena and allows unifying the Mueller and Jones calculi in polarization optics.
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spelling doaj.art-b3a242aac259425c8802883f66dbb1de2022-12-22T02:17:51ZengMDPI AGEntropy1099-43002019-07-0121770510.3390/e21070705e21070705Quantum Features of Macroscopic Fields: Entropy and DynamicsRobert Alicki0International Centre for Theory of Quantum Technologies (ICTQT), University of Gdańsk, 80-308 Gdańsk, PolandMacroscopic fields such as electromagnetic, magnetohydrodynamic, acoustic or gravitational waves are usually described by classical wave equations with possible additional damping terms and coherent sources. The aim of this paper is to develop a complete macroscopic formalism including random/thermal sources, dissipation and random scattering of waves by environment. The proposed reduced state of the field combines averaged field with the two-point correlation function called single-particle density matrix. The evolution equation for the reduced state of the field is obtained by reduction of the generalized quasi-free dynamical semigroups describing irreversible evolution of bosonic quantum field and the definition of entropy for the reduced state of the field follows from the von Neumann entropy of quantum field states. The presented formalism can be applied, for example, to superradiance phenomena and allows unifying the Mueller and Jones calculi in polarization optics.https://www.mdpi.com/1099-4300/21/7/705classical field theoryquantum open systemsvon Neumann entropyMueller Jones calculi
spellingShingle Robert Alicki
Quantum Features of Macroscopic Fields: Entropy and Dynamics
Entropy
classical field theory
quantum open systems
von Neumann entropy
Mueller Jones calculi
title Quantum Features of Macroscopic Fields: Entropy and Dynamics
title_full Quantum Features of Macroscopic Fields: Entropy and Dynamics
title_fullStr Quantum Features of Macroscopic Fields: Entropy and Dynamics
title_full_unstemmed Quantum Features of Macroscopic Fields: Entropy and Dynamics
title_short Quantum Features of Macroscopic Fields: Entropy and Dynamics
title_sort quantum features of macroscopic fields entropy and dynamics
topic classical field theory
quantum open systems
von Neumann entropy
Mueller Jones calculi
url https://www.mdpi.com/1099-4300/21/7/705
work_keys_str_mv AT robertalicki quantumfeaturesofmacroscopicfieldsentropyanddynamics