Hawking Radiation and Ultraviolet Regulators

TL;DR

This paper demonstrates that Hawking radiation predictions are largely independent of the ultraviolet regularization scheme, confirming that high-energy physics details do not significantly alter the Hawking flux.

Contribution

The study shows that covariant ultraviolet regulators, like Pauli--Villars, do not substantially affect Hawking radiation, supporting the idea of its universality regardless of high-energy physics details.

Findings

Regulator scale contributes exponentially little to Hawking flux

Hawking radiation is robust against different ultraviolet regularizations

Resolved a technical issue relating propagator singularities to Hawking effect

Abstract

Polchinski has argued that the prediction of Hawking radiation must be independent of the details of unknown high-energy physics because the calculation may be performed using `nice slices', for which the adiabatic theorem may be used. If this is so, then any calculation using a manifestly covariant --- and so slice-independent --- ultraviolet regularization must reproduce the standard Hawking result. We investigate the dependence of the Hawking radiation on such a short-distance regulator by calculating it using a Pauli--Villars regularization scheme. We find that the regulator scale, $\Lambda$, only contributes to the Hawking flux by an amount that is exponentially small in the large variable ${\Lambda}/{T_\ssh} \gg 1$, where $T_\ssh$ is the Hawking temperature; in agreement with Polchinski's arguments. We also solve a technical puzzle concerning the relation between the short-distance singularities of the propagator and the Hawking effect.