Microphysical approach to nonequilibrium dynamics of quantum fields

Journal Article · Mon Aug 15 04:00:00 EDT 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.50.2441· OSTI ID:7264513

Gleiser, M; Ramos, R O ^[1]

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1. Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)

We examine the nonequilibrium dynamics of a self-interacting [lambda][phi][sup 4] scalar field theory. Using a real time formulation of finite temperature field theory we derive, up to two loops and [ital O]([lambda][sup 2]), the effective equation of motion describing the approach to equilibrium. We present a detailed analysis of the approximations used in order to obtain a Langevin-like equation of motion, in which the noise and dissipation terms associated with quantum fluctuations obey a fluctuation-dissipation relation. We show that, in general, the noise is colored (time dependent) and multiplicative (couples nonlinearly to the field), even though it is still Gaussian distributed. The noise becomes white in the infinite temperature limit. We also address the effect of couplings to other fields, which we assume play the role of the thermal bath, in the effective equation of motion for [phi]. In particular, we obtain the fluctuation and noise terms due to a quadratic coupling to another scalar field.

• OSTI ID: 7264513
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 50:4; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
662110 -- General Theory of Particles & Fields-- Theory of Fields & Strings-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUATIONS OF MOTION
EQUILIBRIUM
FIELD THEORIES
FLUCTUATIONS
LANGEVIN EQUATION
NOISE
PARTIAL DIFFERENTIAL EQUATIONS
PHI4-FIELD THEORY
QUANTUM FIELD THEORY
SCALAR FIELDS
TEMPERATURE DEPENDENCE
VARIATIONS