Instantaneous vacuum and States of Low Energy for a scalar field in cosmological backgrounds

Abstract

We construct the instantaneous vacuum state for a quantum scalar field coupled to another classical scalar field as described in [1]. We then compare it with the state of low energy constructed for a particular solution. We show that under physically motivated conditions they become very similar.

arXiv comment10 pages, 4 figures, contribution to the proceedings of the "Avenues of Quantum Field Theory in Curved Space-time" conference, Genova, September 2022