Theoretical study of stimulated and spontaneous Hawking effects from an acoustic black hole in a hydrodynamically flowing fluid of light

TL;DR

This paper provides a theoretical framework for detecting analog Hawking radiation in a flowing exciton-polariton condensate, proposing experiments to measure Hawking temperature and analyze correlated excitations.

Contribution

It introduces a method to observe and characterize analog Hawking effects in a hydrodynamically flowing fluid of light using pump-probe spectroscopy and correlation analysis.

Findings

Dependence of stimulated Hawking effect on pump-probe detuning

Emergence of a resonant cavity for sound waves

Identification of correlated Bogoliubov excitations

Abstract

We propose an experiment to detect and characterize the analog Hawking radiation in an analog model of gravity consisting of a flowing exciton-polariton condensate. Under a suitably designed coherent pump configuration, the condensate features an acoustic event horizon for sound waves that at the semiclassical level is equivalent to an astrophysical black hole horizon. We show that a continuous-wave pump-and-probe spectroscopy experiment allows to measure the analog Hawking temperature from the dependence of the stimulated Hawking effect on the pump-probe detuning. We anticipate the appearance of an emergent resonant cavity for sound waves between the pump beam and the horizon, which results in marked oscillations on top of an overall exponential frequency dependence. We finally analyze the spatial correlation function of density fluctuations and identify the hallmark features of the correlated pairs of Bogoliubov excitations created by the spontaneous Hawking process, as well as novel signatures characterizing the emergent cavity.