Acoustic analogue of Hawking radiation in quantized circular superflows of Bose-Einstein condensates

TL;DR

This paper proposes a method to emulate Hawking radiation using acoustic excitations in a Bose-Einstein condensate with a ring shape, revealing how geometry influences the formation of sonic black holes and their stability.

Contribution

It introduces a novel setup for creating sonic black and white horizons in a ring-shaped BEC and analyzes how the ring radius and modes affect Hawking radiation analogs.

Findings

Density correlation patterns indicate Hawking radiation analogs.

A minimum ring radius is required for emulation.

White-hole horizon slope suppresses instabilities.

Abstract

We propose emulation of Hawking radiation (HR) by means of acoustic excitations propagating on top of persistent current in an atomic Bose-Einstein condensate (BEC) loaded in an annular confining potential. The setting is initially created as a spatially uniform one, and then switches into a nonuniform configuration, while maintaining uniform BEC density. The eventual setting admits the realization of sonic black and white event horizons with different slopes of the local sound speed. A smooth slope near the white-hole horizon suppresses instabilities in the supersonic region. It is found that tongue-shaped patterns of the density-density correlation function, which represent the acoustic analog of HR, are strongly affected by the radius of the ring-shaped configuration and number of discrete acoustic modes admitted by it. There is a minimum radius that enables the emulation of HR. We also briefly discuss a possible similarity of properties of the matter-wave sonic black holes to the known puzzle of the stability of Planck-scale primordial black holes in quantum gravity.