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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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 |
work_keys_str_mv |
AT pinggao ghostbustersunitarityandcausalityofnonequilibriumeffectivefieldtheories AT paologlorioso ghostbustersunitarityandcausalityofnonequilibriumeffectivefieldtheories AT hongliu ghostbustersunitarityandcausalityofnonequilibriumeffectivefieldtheories |
_version_ |
1725284172487983104 |