Signatures of Energy Flux in Particle Production: A Black Hole Birth Cry and Death Gasp

TL;DR

This paper investigates the signatures of energy flux during black hole formation and evaporation, revealing that the birth cry is detectable through particle counts, but the death gasp is not, using a new exactly unitary model.

Contribution

It introduces a new exactly unitary solution modeling black hole energy flux, showing distinct observable signatures for black hole birth and death.

Findings

Birth cry detectable via particle count

Death gasp not observable through particle flux

Characteristic positive energy burst and thermal plateau observed

Abstract

It is recently argued that if the Hawking radiation process is unitary, then a black hole's mass cannot be monotonically decreasing. We examine the time dependent particle count and negative energy flux in the non-trivial conformal vacuum via the moving mirror approach. A new, exactly unitary solution is presented which emits a characteristic above-thermal positive energy burst, a thermal plateau, and negative energy flux. It is found that the characteristic positive energy flare and thermal plateau is observed in the particle outflow. However, the results of time dependent particle production show no overt indication of negative energy flux. Therefore, a black hole's birth cry is detectable by asymptotic observers via particle count, whereas its death gasp is not.