Quantum Ergoregion Instability

TL;DR

This paper demonstrates that ergoregions without horizons can spontaneously emit energy through a quantum instability, akin to laser amplification, differing from black hole radiation.

Contribution

It introduces the concept of quantum ergoregion instability in rotating stars, showing spontaneous energy emission without an event horizon, modeled via canonical quantization.

Findings

Ergoregions can spontaneously radiate energy without horizons.

Quantum instability in ergoregions resembles laser amplification.

The model uses canonical quantization of a scalar field.

Abstract

We have shown that, as in the case of black holes, an ergosphere itself with no event horizon inside can evaporate spontaneously, giving energy radiation to spatial infinity until the ergoregion disappears. However, the feature of his quantum ergoregion instability is very much different from black hole radiation. It is rather analogous to a laser amplification. This analysis is based on the canonical quantization of a neutral scalar field in the presence of unstable modes characterized by complex frequencies in a simple model for a rapidly rotating star.