On the thermodynamics of moving bodies

Abstract

We model the situation in which a photon detector moves with constant velocity in a Minkowski heat-bath by considering an Unruh-DeWitt detector, with variable energy gap $\hslash \omega$, moving on a brane, at a non-zero (Unruh) temperature $T$ due to acceleration in an orthogonal direction. We compute the angular response for a 2-brane. At low velocity we find agreement with the standard Doppler shift formula in the limit $\hslash \omega \gg T$ in which the photon gas is classical; otherwise there is a discrepancy, which we attribute to angular-dependence of the induced emission rate. At relativistic velocities our result disagrees with the standard formula even when $\hslash \omega \gg T$, and above a critical velocity there is no response from the detector within a `backward' cone. We discuss potential implications for observations of the cosmic microwave background radiation.

v3 Substantially expanded, new sections, references and comments added. v4 Published version in CQG. 18 pages, 4 figures

References in corpus (5)

• How often does the Unruh-DeWitt detector click? Regularisation by a spatial profile
• The Fulling-Unruh effect in general stationary accelerated frames
• Inverse Temperature 4-vector in Special Relativity
• Accelerating Branes and Brane Temperature
• Relativistic Kinematics and Stationary Motions

Cited by in corpus (5)

• Gravitational memory for uniformly accelerated observers
• Response of a uniformly accelerated detector to massless Rarita-Schwinger fields in vacuum
• Drift, Drag and Brownian motion in the Davies-Unruh bath
• All the Stationary Vacuum States of De Sitter Space
• Unruh temperatures in circular and drifted Rindler motions