Limits to the analog Hawking temperature in a Bose-Einstein condensate

Abstract

Quasi-one-dimensional outflow from a dilute gas Bose-Einstein condensate reservoir is a promising system for the creation of analog Hawking radiation. We use numerical modeling to show that stable sonic horizons exist in such a system under realistic conditions, taking into account the transverse dimensions and three-body loss. We find that loss limits the analog Hawking temperatures achievable in the hydrodynamic regime, with sodium condensates allowing the highest temperatures. A condensate of $30\phantom{\rule{0.2em}{0ex}}000$ atoms, with transverse confinement frequency ${\ensuremath{\omega}}_{\ensuremath{\perp}}=6800\ifmmode\times\else\texttimes\fi{}2\ensuremath{\pi}\phantom{\rule{0.3em}{0ex}}\mathrm{Hz}$, yields horizon temperatures of about $20\phantom{\rule{0.3em}{0ex}}\mathrm{nK}$ over a period of $50\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$. This is at least four times higher than for other atoms commonly used for Bose-Einstein condensates.