# 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={arXiv: High Energy Physics - Phenomenology}, year={2015} }

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 \emph{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…

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