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Nonequilibrium time evolution of the spectral function in quantum field theory / Gert Aarts, Jürgen Berges

Physical Review D, Volume: "D64", Issue: 10, Start page: 105010

Swansea University Author: Gert Aarts

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Abstract

Transport or kinetic equations are often derived assuming a quasi-particle (on-shell) representation of the spectral function. We investigate this assumption using a three-loop approximation of the 2PI effective action in real time, without a gradient expansion or on-shell approximation. For a scala...

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Published in: Physical Review D
ISSN: 0556-2821 1089-4918
Published: 2001
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URI: https://cronfa.swan.ac.uk/Record/cronfa22614
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Abstract: Transport or kinetic equations are often derived assuming a quasi-particle (on-shell) representation of the spectral function. We investigate this assumption using a three-loop approximation of the 2PI effective action in real time, without a gradient expansion or on-shell approximation. For a scalar field in 1+1 dimensions the nonlinear evolution, including the integration over memory kernels, can be solved numerically. We find that a spectral function approximately described by a nonzero width emerges dynamically. During the nonequilibrium time evolution the Wigner transformed spectral function is slowly varying, even in presence of strong qualitative changes in the effective particle distribution. These results may be used to make further analytical progress towards a quantum Boltzmann equation including off-shell effects and a nonzero width.
Item Description: @articleAarts:2001qa, author = "Aarts, Gert and Berges, Juergen", title = "Nonequilibrium time evolution of the spectral function in quantum field theory", journal = "Phys.Rev.", volume = "D64", pages = "105010", doi = "10.1103/PhysRevD.64.105010", year = "2001", eprint = "hep-ph/0103049", archivePrefix = "arXiv", primaryClass = "hep-ph", reportNumber = "HD-THEP-01-11", SLACcitation = "%%CITATION = HEP-PH/0103049;%%",
College: College of Science
Issue: 10
Start Page: 105010