On the puzzle of Bremsstrahlung as described by coaccelerated observers

TL;DR

This paper examines the paradoxes in quantum field theory related to Bremsstrahlung as seen by inertial and accelerated observers, focusing on how the field's state changes across different spacetime regions.

Contribution

It provides a detailed analysis of the apparent contradictions in the quantum description of Bremsstrahlung from different observer perspectives, clarifying the role of thermal states and field changes.

Findings

Thermal equilibrium in one wedge does not alter the field state there.

The quantum field state on the future wedge must change to account for energy-momentum.

The paper resolves paradoxes related to observer-dependent descriptions of radiation.

Abstract

We consider anew some puzzling aspects of the equivalence of the quantum field theoretical description of Bremsstrahlung from the inertial and accelerated observer's perspectives. More concretely, we focus on the seemingly paradoxical situation that arises when noting that the radiating source is in thermal equilibrium with the thermal state of the quantum field in the wedge in which it is located, and thus its presence does not change there the state of the field, while it clearly does not affect the state of the field on the opposite wedge. How then is the state of the quantum field on the future wedge changed, as it must in order to account for the changed energy momentum tensor there? This and related issues are carefully discussed.