Insensitivity of Hawking radiation to an invariant Planck-scale cutoff

TL;DR

Hawking radiation remains unaffected by a covariant Planck-scale cutoff, suggesting its robustness and relevance for quantum gravity theories that preserve Lorentz symmetry.

Contribution

The paper demonstrates that Hawking radiation is insensitive to an invariant Planck-scale cutoff when analyzed covariantly, challenging the need for trans-Planckian physics in its derivation.

Findings

Hawking radiation is robust against covariant Planck-scale cutoffs.

The derivation of Hawking radiation does not require trans-Planckian physics.

Implications for quantum gravity theories preserving Lorentz symmetry.

Abstract

A disturbing aspect of Hawking's derivation of black hole radiance is the need to invoke extreme conditions for the quantum field that originates the emitted quanta. It is widely argued that the derivation requires the validity of the conventional relativistic field theory to arbitrarily high, trans-Planckian scales. We stress in this note that this is not necessarily the case if the question is presented in a covariant way. We point out that Hawking radiation is immediately robust against an invariant Planck-scale cutoff. This important feature of Hawking radiation is relevant for a quantum gravity theory that preserves, in some way, the Lorentz symmetry.