Bogoliubov-Cerenkov radiation in a Bose-Einstein condensate flowing against an obstacle

TL;DR

This paper investigates the phenomenon of Bogoliubov-Cerenkov radiation in a flowing Bose-Einstein condensate, demonstrating how density modulations arise from Cerenkov emission of excitations when flowing against an obstacle.

Contribution

It provides experimental observations and numerical simulations linking density modulations to Bogoliubov Cerenkov radiation in a flowing condensate.

Findings

Reproduces experimental density profiles with Gross-Pitaevskii simulations.

Identifies phonon and single-particle regions as sources of wavefronts and precursors.

Connects density modulations to Cerenkov emission of Bogoliubov excitations.

Abstract

We study the density modulation that appears in a Bose-Einstein condensate flowing with supersonic velocity against an obstacle. The experimental density profiles observed at JILA are reproduced by a numerical integration of the Gross-Pitaevskii equation and then interpreted in terms of Cerenkov emission of Bogoliubov excitations by the defect. The phonon and the single-particle regions of the Bogoliubov spectrum are respectively responsible for a conical wavefront and a fan-shaped series of precursors.