A cosmological open quantum system
Abstract
We derive the evolution equation for the density matrix of a UV- and IR- limited band of comoving momentum modes of the canonically normalized scalar degree of freedom in two examples of nearly de Sitter universes. Including the effects of a cubic interaction term from the gravitational action and tracing out a set of longer wavelength modes, we find that the evolution of the system is non-Hamiltonian and non-Markovian. We find linear dissipation terms for a few modes with wavelength near the boundary between system and bath and nonlinear dissipation terms for all modes. The non-Hamiltonian terms persist to late times when the scalar field dynamics is such that the curvature perturbation continues to evolve on super-Hubble scales.
Cite
@article{arxiv.1708.00493,
title = {A cosmological open quantum system},
author = {Sarah Shandera and Nishant Agarwal and Archana Kamal},
journal= {arXiv preprint arXiv:1708.00493},
year = {2018}
}
Comments
5 pages; V2 corrects an error in plots (Fig 2) and adds supplementary material with derivation details; v4 matches published version and corrects a typo in mode-sum expression