Comment on "Insensitivity of Hawking Radiation to an invariant Planck-scale cutoff"

TL;DR

This paper critiques a recent approach to the trans-Planckian problem in Hawking radiation, arguing that the proposed cutoff affects only a minor part of the problematic modes and thus does not resolve the core issue.

Contribution

It provides a critical analysis showing that the cutoff suggested by Agullo et al. minimally impacts the trans-Planckian problem, challenging its effectiveness.

Findings

The cutoff excludes only a small fraction of problematic modes.

The trans-Planckian problem remains largely unaffected by the proposed cutoff.

The insensitivity of Hawking radiation to the cutoff is reaffirmed.

Abstract

I point out that the cutoff introduced by Agullo et al. [Phys.Rev.D80:047503,2009 arXiv:0906.5315] has little impact on the trans-Planckian problem as it is usually understood; it excludes only a small fraction of the problematic modes.