Quantum Gravity signatures in the Unruh effect

TL;DR

This paper investigates how quantum gravity models influence the Unruh effect, revealing characteristic modifications in the detector's emission rate that depend on the underlying quantum spacetime structure.

Contribution

It introduces the 'Unruh dimension' to quantify quantum gravity effects on the Unruh effect and analyzes how different models alter the detector's response.

Findings

Unruh temperature remains unaffected by quantum gravity.

Quantum gravity models with dimensional reduction suppress the Unruh rate at high energies.

Kaluza-Klein theories with extra dimensions enhance the Unruh rate.

Abstract

We study quantum gravity signatures emerging from phenomenologically motivated multiscale models, spectral actions, and Causal Set Theory within the detector approach to the Unruh effect. We show that while the Unruh temperature is unaffected, Lorentz-invariant corrections to the two-point function leave a characteristic fingerprint in the induced emission rate of the accelerated detector. Generically, quantum gravity models exhibiting dynamical dimensional reduction exhibit a suppression of the Unruh rate at high energy while the rate is enhanced in Kaluza-Klein theories with compact extra dimensions. We quantify this behavior by introducing the "Unruh dimension" as the effective spacetime dimension seen by the Unruh effect and show that it is related, though not identical, to the spectral dimension used to characterize spacetime in quantum gravity. We comment on the physical origins of these effects and their relevance for black hole evaporation.