Ghostbusters: unitarity and causality of non-equilibrium effective field theories

Abstract: For a non-equilibrium physical system defined along a closed time path (CTP), a key constraint is the so-called largest time equation, which is a consequence of unitarity and implies causality. In this paper, we present a simple proof that if the propagators of a non-equilibrium effective...

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Main Authors: Ping Gao, Paolo Glorioso, Hong Liu
Format: Article
Language:English
Published: SpringerOpen 2020-03-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP03(2020)040
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spelling doaj-6506e49b147a46e0ba0bec11c5eb19122020-11-25T00:42:02ZengSpringerOpenJournal of High Energy Physics1029-84792020-03-012020312010.1007/JHEP03(2020)040Ghostbusters: unitarity and causality of non-equilibrium effective field theoriesPing Gao0Paolo Glorioso1Hong Liu2Center for the Fundamental Laws of Nature, Harvard UniversityKadanoff Center for Theoretical Physics and Enrico Fermi Institute, University of ChicagoCenter for Theoretical Physics, Massachusetts Institute of TechnologyAbstract: For a non-equilibrium physical system defined along a closed time path (CTP), a key constraint is the so-called largest time equation, which is a consequence of unitarity and implies causality. In this paper, we present a simple proof that if the propagators of a non-equilibrium effective action have the proper pole structure, the largest time equation is obeyed to all loop orders. Ghost fields and BRST symmetry are not needed. In particular, the arguments for the proof can also be used to show that if ghost fields are introduced, their contributions vanish.http://link.springer.com/article/10.1007/JHEP03(2020)040Effective Field TheoriesQuantum Dissipative SystemsSupersymmetric Effective Theories
collection DOAJ
language English
format Article
sources DOAJ
author Ping Gao
Paolo Glorioso
Hong Liu
spellingShingle Ping Gao
Paolo Glorioso
Hong Liu
Ghostbusters: unitarity and causality of non-equilibrium effective field theories
Journal of High Energy Physics
Effective Field Theories
Quantum Dissipative Systems
Supersymmetric Effective Theories
author_facet Ping Gao
Paolo Glorioso
Hong Liu
author_sort Ping Gao
title Ghostbusters: unitarity and causality of non-equilibrium effective field theories
title_short Ghostbusters: unitarity and causality of non-equilibrium effective field theories
title_full Ghostbusters: unitarity and causality of non-equilibrium effective field theories
title_fullStr Ghostbusters: unitarity and causality of non-equilibrium effective field theories
title_full_unstemmed Ghostbusters: unitarity and causality of non-equilibrium effective field theories
title_sort ghostbusters: unitarity and causality of non-equilibrium effective field theories
publisher SpringerOpen
series Journal of High Energy Physics
issn 1029-8479
publishDate 2020-03-01
description Abstract: For a non-equilibrium physical system defined along a closed time path (CTP), a key constraint is the so-called largest time equation, which is a consequence of unitarity and implies causality. In this paper, we present a simple proof that if the propagators of a non-equilibrium effective action have the proper pole structure, the largest time equation is obeyed to all loop orders. Ghost fields and BRST symmetry are not needed. In particular, the arguments for the proof can also be used to show that if ghost fields are introduced, their contributions vanish.
topic Effective Field Theories
Quantum Dissipative Systems
Supersymmetric Effective Theories
url http://link.springer.com/article/10.1007/JHEP03(2020)040
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AT paologlorioso ghostbustersunitarityandcausalityofnonequilibriumeffectivefieldtheories
AT hongliu ghostbustersunitarityandcausalityofnonequilibriumeffectivefieldtheories
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