A new algorithm counts degrees of freedom in open EFTs from equations of motion using dual advanced equations for non-Lagrangian systems with constraints and gauges.
An effective field theory during inflation: reduced density matrix and its quantum master equation
3 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We study the power spectrum of super-Hubble fluctuations of an inflaton-like scalar field, the "system", coupled to another scalar field, the "environment" during de Sitter inflation. We obtain the reduced density matrix for the inflaton fluctuations by integrating out the environmental degrees of freedom. These are considered to be massless and conformally coupled to gravity as a \emph{proxy} to describe degrees of freedom that remain sub-Hubble all throughout inflation. The time evolution of the density matrix is described by a quantum master equation, which describes the decay of the vacuum state, the production of particles and correlated pairs and quantum entanglement between super and sub-Hubble degrees of freedom. The quantum master equation provides a non-perturbative resummation of secular terms from self-energy (loop) corrections to the inflaton fluctuations. In the case studied here these are Sudakov-type double logarithms which result in the \emph{decay} of the power spectrum of inflaton fluctuations upon horizon crossing with a concomitant violation of scale invariance. The reduced density matrix and its quantum master equation furnish a powerful non-perturbative framework to study the effective field theory of long wavelength fluctuations by tracing short wavelength degrees of freedom.
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Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.
An expression is derived to compute time-dependent Wigner functions directly from initial values in open quantum systems of a non-relativistic particle with a general environment.
citing papers explorer
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Counting Degrees of Freedom in Open Effective Theories
A new algorithm counts degrees of freedom in open EFTs from equations of motion using dual advanced equations for non-Lagrangian systems with constraints and gauges.
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Schwinger-Keldysh Path Integral for Gauge theories
Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.
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Directly computing Wigner functions for open quantum systems
An expression is derived to compute time-dependent Wigner functions directly from initial values in open quantum systems of a non-relativistic particle with a general environment.