Soliton Diffusion as a Signature of Hawking Radiation in Bose-Einstein Condensates

TL;DR

This paper proposes detecting analog Hawking radiation in Bose-Einstein condensates by measuring the diffusion of a dark soliton, which acts as an accessible signal of the radiation's presence.

Contribution

It introduces a novel method to observe Hawking radiation in BECs through soliton diffusion, providing a more detectable signature than direct quantum measurements.

Findings

Dark soliton diffusion correlates with Hawking temperature.

Soliton diffusion is significantly easier to measure than Hawking quanta.

The scheme enables experimental detection of analog Hawking radiation.

Abstract

We propose a scheme to detect analog Hawking radiation (HR) in an atomic Bose-Einstein condensate (BEC) through measuring the diffusion of a dark soliton. The HR is generated by changing the transverse trapping potential of the BEC to obtain a background flow, which is subsonic in downstream and supersonic in upstream, satisfying the condition of black hole horizon. When the system is in thermal equilibrium at Hawking temperature, a dark soliton is created in the upstream. Due to the influence of the HR, the motion of the dark soliton is similar to a Brownian particle and hence exhibits an apparent diffusion, which can be measured and be taken as a signal of the HR. Since the dark soliton is much "heavier" than Hawking quanta, its diffusion is much easier detectable than the Hawking quanta themselves.