Dynamics of Bose condensed gases in highly deformed traps

TL;DR

This paper analyzes the behavior of Bose condensed gases in highly deformed traps, deriving explicit hydrodynamic results for low-energy modes and sound propagation in asymmetric geometries.

Contribution

It provides a unified analytical framework for understanding normal modes and sound in highly asymmetric Bose condensates, including large quantum number regimes.

Findings

Explicit dispersion relations for low-energy modes in asymmetric traps

Identification of phonon regimes in cigar and disk geometries

Discussion of sound propagation in cylindrical and one-dimensional configurations

Abstract

We provide a unified investigation of normal modes and sound propagation at zero temperature in Bose condensed gases confined in highly asymmetric harmonic traps and interacting with repulsive forces. By using hydrodynamic theory for superfluids we obtain explicit analytic results for the dispersion law of the low energy discretized modes for both cigar and disk shaped geometries, including the regime of large quantum numbers where discrete modes can be identified with phonons. The correspondence with sound propagation in cylindrical traps and the one-dimensional nature of cigar type configurations are explicitly discussed.