# Entropy evolution of moving mirrors and the information loss problem

## TL;DR

This paper explores how different moving mirror trajectories in 2D quantum field theory can model various proposed solutions to the black hole information loss paradox, revealing conflicts between entanglement and semi-classical views.

## Contribution

It introduces a novel analogy between mirror trajectories and black hole information scenarios, analyzing their implications for unitarity and firewalls.

## Key findings

- Last burst cannot contain enough information.
- Slowly emitting radiation can restore unitarity.
- Stopping mirrors generate firewall-like emissions.

## Abstract

We investigate the entanglement entropy and the information flow of two-dimensional moving mirrors. Here we point out that various mirror trajectories can help to mimic different candidate resolutions to the information loss paradox following the semi-classical quantum field theory: (i) a suddenly stopping mirror corresponds to the assertion that all information is attached to the last burst, (ii) a slowly stopping mirror corresponds to the assertion that thermal Hawking radiation carries information, and (iii) a long propagating mirror corresponds to the remnant scenario. Based on such analogy, we find that the last burst of a black hole cannot contain enough information, while slowly emitting radiation can restore unitarity. For all cases, there is an apparent inconsistency between the picture based on quantum entanglements and that based on the semi-classical quantum field theory. Based on the quantum entanglement theory, a stopping mirror will generate a firewall-like violent emission which is in conflict with notions based on the semi-classical quantum field theory.