Quantum depletion signature of emerging sonic horizons in a quasi-one-dimensional Bose-Einstein condensate
Caio C. Holanda Ribeiro, Sang-Shin Baak, Uwe R. Fischer
Abstract
We consider the quasi-one-dimensional (quasi-1D) model of a sonic black hole in a dilute Bose-Einstein condensate. It is shown that an accurate treatment of the dimensional reduction to quasi-1D leads to a finite condensate quantum depletion even for axially infinite systems, and an intrinsic nonthermality of the black hole radiation spectrum. By calculating the depletion, we derive a {\em first-order} many-body signature of the sonic horizon, represented by a distinct peak in the depletion power spectrum. This peak constitutes a readily experimentally accessible tool to detect quantum sonic horizons even when a negligible Hawking radiation flux is created by the black hole.