Inconsistency with De Sitter Spacetime in a New Approach to Gravitational Particle Production

TL;DR

This paper critically examines a new proposed mechanism for gravitational particle production, revealing significant inconsistencies with established de Sitter spacetime predictions and highlighting its limitations for various scalar couplings.

Contribution

The paper identifies and demonstrates the inconsistencies of a recent approach to particle production in de Sitter space, challenging its validity and applicability.

Findings

Overestimates de Sitter temperature by a factor of 4.3

Overestimates particle production rate by a factor of 52

Predicts negative production for conformally coupled scalars

Abstract

We study a claimed new mechanism for particle production and black hole evaporation through a spatially dependent temperature. This new temperature is comparable to the Hawking result near the black hole, but is very small far away, and therefore could be a small correction. Here we apply the proposed reasoning to the case of de Sitter space, finding that it over predicts the de Sitter temperature of a minimally coupled scalar by factor of $\approx 4.3$ and over predicts the particle production rate by a factor of $\approx 52$. For non-minimally coupled scalars, it has other various problems; it predicts a negative particle production for conformal, or nearly conformal, coupled scalars; it predicts unsuppressed productions of heavy scalars. This all demonstrates an inconsistency in the proposed formalism.