Low lying twisting and acoustic modes of a rotating Bose-Einstein condensate

TL;DR

This paper analyzes the low-energy excitations of a rotating Bose-Einstein condensate, identifying acoustic and twisting vortex lattice modes, and derives their spectra using hydrodynamical methods in cylindrical geometries.

Contribution

It introduces a hydrodynamical approach to calculate the elasticity and excitation spectrum of vortex lattices in rotating BECs, highlighting twisting modes.

Findings

Existence of two linear excitation branches in cylindrical geometry

Derivation of the vortex lattice elasticity coefficient

Spectrum calculation for 3D harmonic traps with cylindrical symmetry

Abstract

We present a calculation of the low lying spectrum of a rotating Bose-Einstein condensate. We show that in a cylindrical geometry, there exist two linear branches, one associated to usual acoustic excitation, the other corresponding to a twisting mode of the vortex lattice. Using a hydrodynamical approach we derive the elasticity coefficient of the vortex lattice and calculate the spectrum of condensate in a three dimensionnal harmonic trap with cylindrical symmetry.