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arXiv · 0812.1934

Nonequilibrium Dynamics of Scalar Fields in a Thermal Bath

A. Anisimov·W. Buchmueller·M. Drewes·S. Mendizabal
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Abstract

We study the approach to equilibrium for a scalar field which is coupled to a large thermal bath. Our analysis of the initial value problem is based on Kadanoff-Baym equations which are shown to be equivalent to a stochastic Langevin equation. The interaction with the thermal bath generates a temperature-dependent spectral density, either through decay and inverse decay processes or via Landau damping. In equilibrium, energy density and pressure are determined by the Bose-Einstein distribution function evaluated at a complex quasi-particle pole. The time evolution of the statistical propagator is compared with solutions of the Boltzmann equations for particles as well as quasi-particles. The dependence on initial conditions and the range of validity of the Boltzmann approximation are determined.

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A. Anisimov, W. Buchmueller, M. Drewes, S. Mendizabal. 2008-12-22. Nonequilibrium Dynamics of Scalar Fields in a Thermal Bath. https://doi.org/10.1016/j.aop.2009.01.001

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