The decoherence and interference of cosmological arrows of time for a de Sitter universe with quantum fluctuations

TL;DR

This paper investigates how quantum fluctuations and environment-induced decoherence influence the interference and decoherence of opposite cosmological arrows of time in a de Sitter universe, highlighting the quantum-to-classical transition.

Contribution

It models the superposition of contracting and expanding universe solutions and quantifies decoherence effects caused by scalar vacuum modes crossing the Hubble horizon.

Findings

Interference between opposite arrows of time is suppressed by environment-induced decoherence.

Decoherence effects are quantified in terms of scalar vacuum mode crossing Hubble horizon.

Interference impacts the expectation values of observable field mode correlations.

Abstract

We consider the superposition of two semiclassical solutions of the Wheeler-DeWitt equation for a de Sitter universe, describing a quantized scalar vacuum propagating in a universe that is contracting in one case and expanding in the other, each identifying a opposite cosmological arrow of time. We discuss the suppression of the interference terms between the two arrows of time due to environment-induced decoherence caused by modes of the scalar vacuum crossing the Hubble horizon. Furthermore, we quantify the effect of the interference on the expectation value of the observable field mode correlations, with respect to an observer that we identify with the spatial geometry.