Open quantum system approach to Gibbons-Hawking effect of de Sitter space-time

TL;DR

This paper models a two-level detector in de Sitter space as an open quantum system, demonstrating that it thermalizes at the Gibbons-Hawking temperature due to interactions with quantum fields, revealing the thermal nature of the spacetime.

Contribution

It applies open quantum system techniques to explain the Gibbons-Hawking effect as a thermalization process involving decoherence and dissipation.

Findings

Detector reaches thermal equilibrium at Gibbons-Hawking temperature

Thermalization occurs regardless of initial state

Gibbons-Hawking effect interpreted as open quantum system thermalization

Abstract

We analyze, in the paradigm of open quantum systems, the reduced dynamics of a freely-falling two-level detector in de Sitter space-time in weak interaction with a reservoir of fluctuating quantized conformal scalar fields in the de Sitter invariant vacuum. We find that the detector is asymptotically driven to a thermal state at the Gibbons-Hawking temperature, regardless of its initial state. Our discussion therefore shows that the Gibbons-Hawking effect of de Sitter space-time can be understood as a manifestation of thermalization phenomena that involves decoherence and dissipation in open quantum systems.