Robustness of entanglement in Hawking radiation for optical systems immersed in thermal baths

TL;DR

This paper demonstrates that optical analog systems can maintain Hawking radiation entanglement despite high ambient thermal fluctuations, due to relativistic effects and dispersion, unlike gravitational systems.

Contribution

It reveals a novel robustness mechanism in optical analogs where relativistic motion and dispersion preserve entanglement under thermal noise.

Findings

Relativistic motion and dispersion protect entanglement from thermal effects.

Optical systems can sustain entanglement at ambient temperatures much higher than Hawking temperature.

Thermal fluctuations do not significantly diminish Hawking entanglement in these systems.

Abstract

Entanglement is the quantum signature of Hawking's particle pair-creation from causal horizons, for gravitational and analog systems alike. Ambient thermal fluctuations, ubiquitous in realistic situations, strongly affects the entanglement generated in the Hawking process, completely extinguishing it when the ambient temperature is comparable to the Hawking temperature. In this work, we show that optical analog systems have a built-in robustness to thermal fluctuations which are at rest in the laboratory. In such systems, horizons move relative to the laboratory frame at velocities close to the speed of light. We find that a subtle interplay between this relative velocity and dispersion protects the Hawking-generated entanglement -- allowing ambient temperatures several orders of magnitude larger than the Hawking temperature without significantly affecting entanglement.