Understanding Hawking radiation in the framework of open quantum systems

TL;DR

This paper models Hawking radiation as an open quantum system, showing that a detector interacting with quantum fields near a black hole exhibits excitation probabilities consistent with thermal Hawking radiation.

Contribution

It introduces a novel open quantum systems approach to analyze Hawking radiation, using a master equation for a detector interacting with quantum fields near a black hole.

Findings

Detector spontaneously excites in Unruh and Hartle-Hawking vacua

Excitation probabilities match thermal radiation at Hawking temperature

Reproduces Hawking effect within open quantum systems framework

Abstract

We study the Hawking radiation in the framework of open quantum systems by examining the time evolution of a detector (modelled by a two-level atom) interacting with vacuum massless scalar fields. The dynamics of the detector is governed by a master equation obtained by tracing over the field degrees of freedom from the complete system. The nonunitary effects are studied by analyzing the time behavior of a particular observable of the detector, i.e., its admissible state, in the Unruh, Hartle-Hawking, as well as Boulware vacua outside a Schwarzschild black hole. We find that the detector in both the Unruh and Hartle-Hawking vacua would spontaneously excite with a nonvanishing probability the same as what one would obtain if there is thermal radiation at the Hawking temperature from the black hole, thus reproducing the basic results concerning the Hawking effect in the framework of open quantum systems.