Regular Article - Theoretical Physics
Stochastic inflaton wave equation from an expanding environment
Institute of Theoretical Physics, University of Wroclaw, 50-204, Wrocław, Poland
* e-mail: firstname.lastname@example.org
Accepted: 24 March 2020
Published online: 13 April 2020
We discuss the inflaton in an environment of scalar fields on flat and curved manifolds. We average over the environmental fields . We study a contribution of superhorizon as well as subhorizon modes . As a result we obtain a stochastic wave equation with a friction and noise. We show that in the subhorizon regime in field theory a finite number of fields is sufficient to produce a friction and diffusion owing to the infinite number of degrees of freedom corresponding to different in . We investigate the slow roll and the Markovian approximations to the stochastic wave equation. A determination of the metric from the stochastic Einstein–Klein–Gordon equations is briefly discussed.
© The Author(s), 2020