Experimental observation of a Rindler horizon

TL;DR

This paper reports experimental evidence of a Rindler horizon at CERN-NA63, linking observed radiation spectra to Unruh thermodynamics, and demonstrates measurement of fundamental constants like positron mass through these phenomena.

Contribution

It provides the first experimental confirmation of a Rindler horizon and its thermodynamics in high-energy particle experiments, connecting Unruh effect to measurable spectra.

Findings

Confirmed the presence of a Rindler horizon at CERN-NA63.

Linked radiation entropy to photon number, demonstrating Unruh thermodynamics.

Measured positron mass using the radiation spectrum.

Abstract

In this manuscript we confirm the presence of a Rindler horizon at CERN-NA63 by exploring its thermodynamics induced by the Unruh effect in their high energy channeling radiation experiments. By linking the entropy of the emitted radiation to the photon number, we find the measured spectrum to be a simple manifestation of the second law of Rindler horizon thermodynamics and thus a direct measurement of the recoil Fulling-Davies-Unruh (FDU) temperature. Moreover, since the experiment is born out of an ultra-relativistic positron, and the FDU temperature is defined in the proper frame, we find that temperature boosts as a length and thus fast objects appear colder. The spectrum also provides us with a simple setting to measure fundamental constants, and we employ it to measure the positron mass.