On the Universality of the Hawking Effect

TL;DR

This paper investigates the robustness of the Hawking effect against high-energy modifications, proposing conditions under which it persists and presenting counterexamples that challenge its universality, thus leaving the question open.

Contribution

It introduces general conditions for ultra-high-energy degrees of freedom to reproduce Hawking radiation and provides models and counterexamples that test its universality.

Findings

Hawking effect can be reproduced under certain high-energy conditions

Counterexamples show deviations from Hawking radiation without unphysical assumptions

The universality of Hawking radiation depends on Planckian physics details

Abstract

Addressing the question of whether the Hawking effect depends on degrees of freedom at ultra-high (e.g., Planckian) energies/momenta, we propose three rather general conditions on these degrees of freedom under which the Hawking effect is reproduced to lowest order. As a generalization of Corley's results, we present a rather general model based on non-linear dispersion relations satisfying these conditions together with a derivation of the Hawking effect for that model. However, we also demonstrate counter-examples, which do not appear to be unphysical or artificial, displaying strong deviations from Hawking's result. Therefore, whether real black holes emit Hawking radiation remains an open question and could give non-trivial information about Planckian physics. PACS: 04.70.Dy, 04.62.+v, 04.60.-m, 04.20.Cv.