# Effective field theory out of equilibrium: Brownian quantum fields

@article{Boyanovsky2015EffectiveFT,
title={Effective field theory out of equilibrium: Brownian quantum fields},
author={Daniel Boyanovsky},
journal={New Journal of Physics},
year={2015},
volume={17}
}
• D. Boyanovsky
• Published 28 February 2015
• Physics
• New Journal of Physics
The emergence of an effective field theory out of equilibrium is studied in the case in which a light field—the system—interacts with very heavy fields in a finite temperature bath. We obtain the reduced density matrix for the light field, its time evolution is determined by an effective action that includes the influence action from correlations of the heavy degrees of freedom. The non-equilibrium effective field theory yields a Langevin equation of motion for the light field in terms of…
27 Citations
Integrating out high energy degrees of freedom to yield a low energy effective field theory leads to a loss of information with a concomitant increase in entropy. We obtain the effective field theory
A covariant description of quantum matter fields in the early universe underpins models for the origin of species, e.g. baryogenesis and dark matter production. In nearly all cases the relevant
The conventional Brownian motion in harmonic systems has provided a deep understanding of a great diversity of dissipative phenomena. We address a rather fundamental microscopic description for the
• Physics
• 2015
A bstractScalar fields appear in many theories beyond the Standard Model of particle physics. In the early universe, they are exposed to extreme conditions, including high temperature and rapid
• Physics
Physical Review D
• 2018
We consider an infrared truncated massive minimally coupled scalar field with a quartic self-interaction in the locally de Sitter background of an inflating universe. We compute the two-point
• Physics
Physical Review D
• 2018
Inspired by holographic Wilsonian renormalization, we consider coarse graining a quantum system divided between short distance and long distance degrees of freedom, coupled via the Hamiltonian.
• Physics
Universe
• 2022
We provide a description of interacting quantum fields in terms of density matrices for any occupation numbers in Fock space in a momentum basis. As a simple example, we focus on a real scalar field
• Physics
• 2016
Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary e-folds.
• Physics
• 2017
To model a realistic situation for the beginning we consider massive real scalar $\phi^4$ theory in a (1+1)-dimensional asymptotically static Minkowski spacetime with an intermediate stage of
We study the thermalization of a scalar ﬁeld Φ coupled to two other scalar ﬁelds χ 1 , 2 that constitute a bath in thermal equilibrium. For a range of masses the Φ propagator features threshold and

## References

SHOWING 1-10 OF 85 REFERENCES

• Physics
• 1997
We explore how the existence of a field with a heavy mass influences the low energy dynamics of a quantum field with a light mass by expounding the stochastic characters of their interactions which
• Physics
Physical review. D, Particles and fields
• 1995
It is shown that when the quantum to classical transition is properly treated, with due consideration of the relation of decoherence, noise, fluctuation and dissipation, the amplitude of density contrast predicted falls in the acceptable range without requiring a fine tuning of the coupling constant of the inflation field.
• Physics
• 1999
The aim of this paper is twofold: to probe the statistical mechanical properties of interacting quantum fields, and to provide a field theoretical justification for a stochastic source term in the
• Physics, Geology
• 2013
A bstractWe use the in-in or Schwinger-Keldysh formalism to explore the construction and interpretation of effective field theories for time-dependent systems evolving out of equilibrium. Starting
• Physics
• 2014
A bstractWe identify the effective field theory describing the physics of super-Hubble scales and show it to be a special case of a class of effective field theories appropriate to open systems. Open
• Physics
Physical review. D, Particles and fields
• 1994
The stochastic approach is further developed to produce a method of calculating an arbitrary anomalously large correlation function of the scalar field in the de Sitter background, and expressions for the two-point correlation function in the equilibrium state, correlation time, and spatial physical correlation radius are presented.
• Physics
• 1998
The real time evolution of non-equilibrium expectation values with soft length scales ∼ k −1 > (eT) −1 is solved in hot scalar electrodynamics, with a view towards understanding relaxational
• Physics
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
• 1999
A Markovian approximation that includes off-shell contributions and the usual Boltzmann equation (energy conserving) are obtained from the quantum kinetic equation in the limit of wide separation of time scales upon different coarse-graining assumptions.
• Physics
• 1999
Pair annihilation of heavy stable particles that occurs in the early universe is investigated, and a quantum kinetic equation for the momentum distribution of the annihilating particle is derived,
• Physics
Physical review. D, Particles and fields
• 1989
This model illustrates that the appearance of dissipative behavior from the back reaction of particle creation in quantum fields is a general feature and suggests that the role of gravity in the display of dissipatives behavior in semiclassical processes is not unique.