Hawking radiation from black holes in de Sitter spaces

TL;DR

This paper extends the anomaly cancellation method to derive Hawking radiation from both the event horizon and cosmological horizon of various black holes in de Sitter space, confirming the fluxes match expected Hawking radiation.

Contribution

It demonstrates that gauge and gravitational anomalies at the horizons account for Hawking radiation in de Sitter black holes, including rotating and purely de Sitter cases.

Findings

Fluxes at horizons match Hawking radiation predictions.

Anomalies at the cosmological horizon differ from those at the event horizon.

Method applies to various black hole types in de Sitter space.

Abstract

Recently, Hawking radiation has been treated, by Robinson and Wilczek, as a compensating flux of the energy momentum tensor required to cancel gavitational anomaly at the event horizon(EH) of a Schwarzschild-type black hole. In this paper, motivated by their work, Hawking radiation from the event horizon(EH) and the de Sitter cosmological horizon(CH) of black holes in de Sitter spaces, specifically including the purely de Sitter black hole, and the static, spherically symmetric Schwarzschild-de Sitter black hole as well as the rotating Kerr-de Sitter black hole, has been studied by anomalies. The result shows that the gauge current and energy momentum tensor fluxes, required to restore gauge invariance and general coordinate covariance at the EH and the CH, are precisely equal to those of Hawking radiation from the EH and the CH, respectively. It should be noted that, gauge and gravitational anomalies taken place at the cosmological horizon(CH) arise from the fact that the effective field theory is formulated inside the CH to integrate out the classically irrelevant outgoing modes at the CH, which is different from those at the black hole horizon(EH).