Analog Hawking radiation from a spin-sonic horizon in a two-component Bose-Einstein condensate

TL;DR

This paper explores analog Hawking radiation in a two-component Bose-Einstein condensate, highlighting experimental advantages and identifying observable signatures of Hawking emission beyond relativistic regimes.

Contribution

It provides a theoretical analysis of Hawking radiation from spin modes in BECs, including both stimulated and spontaneous emission, with semi-analytical and numerical methods.

Findings

Identification of observable signatures of Hawking radiation in spin modes.

Analysis of the massive nature of excitations and associated undulations.

Support from time-dependent simulations validating theoretical predictions.

Abstract

We theoretically study stimulated and spontaneous Hawking emission from an analog horizon for spin modes in a two-component Bose-Einstein condensate, both with and without a coherent coupling between the two components. We highlight the conceptual and practical advantages that these systems offer to the experimental observation of the phenomenon, namely the massive nature of elementary excitations and the experimental accessibility of the different quadratures of the spin excitations. In particular, we go beyond the relativistic regimes previously addressed in the literature, and identify various observables that show a signature of the Hawking process, as well as additional features associated with the massive nature of the modes, such as undulations. Semi-analytical calculations of the scattering properties of the horizon and of two-point correlation functions of the emitted radiation in an ideal stationary setup are supported by time-dependent numerical simulations based on Gross-Pitaevskii and Bogoliubov theory.