On the Response of Particle Detectors in Vaidya Spacetimes

TL;DR

This paper analyzes how particle detectors respond in Vaidya spacetimes, showing their responses depend on their initial state and position relative to collapsing matter, with implications for the information loss paradox.

Contribution

It provides a new calculation of the Wightman function for spherically symmetric modes in Vaidya spacetimes and explores detector responses relative to the collapsing shell.

Findings

Detectors outside the shell respond independently of ingoing null dust configuration.

Detectors inside the shell show response dependence on ingoing null dust.

Results have implications for understanding the information loss paradox.

Abstract

Using the formalism of the interaction picture we calculate an expression for the Wightman function for only the spherically symmetric modes of a quantum Klein-Gordon scalar field in a general Vaidya spacetime with ingoing null dust. It is demonstrated that particle detectors following time-like trajectories that are in the ground state at some time outside of the collapsing shell will respond independently from the configuration of the ingoing null dust if the response is taken at any time outside of the collapsing shell. For detectors that are taken to be in the ground state at a time interior to the shell it is shown that their response will depend on the configuration of the ingoing null dust. Relevance to the information loss paradox is discussed.