Free massive particles with total energy E < mc^2 in curved spacetimes

TL;DR

This paper investigates the behavior of free particles with energy less than their rest energy in various curved spacetimes, using detector models to connect quantum detection with classical GR predictions.

Contribution

It introduces a method to analyze particles with sub-rest-mass energy in curved spacetime and relates quantum detector results to classical general relativity predictions.

Findings

Detection rates align with classical GR predictions

Particles with E < mc^2 are consistent with known physics in curved spacetime

Reconciliation with Earth-based experiments confirms the validity of the approach

Abstract

We analyze free elementary particles with rest mass $m$ and total energy $E < m c^2$ in the Rindler wedge, outside Reissner-Nordstrom black holes and in the spacetime of relativistic (and non-relativistic) stars, and use Unruh-DeWitt-like detectors to calculate the associated particle detection rate in each case. The (mean) particle position is identified with the spatial average of the excitation probability of the detectors, which are supposed to cover the whole space. Our results are shown to be in harmony with General Relativity classical predictions. Eventually we reconcile our conclusions with Earth-based experiments which are in good agreement with $E \geq m c^2$.