Work

Excitation spectrum of vortex-lattice modes in a rotating condensate with a density-dependent gauge potential

Year: 2025

Type: article

Abstract: We investigate the collective excitation spectrum of a quasi-two-dimensional Bose-Einstein condensate trapped in a harmonic confinement with nonlinear rotation induced by a density-dependent gauge potential. Using a Bogoliubov--de Gennes (BdG) analysis, we show that the dipole mode frequency depends strongly on the nonlinear interaction strength, violating Kohn's theorem which is also well complemented by the analytical expression for the dipole and breathing modes obtained employing a variational analysis. We identify four different vortex displacement modes, Tkachenko, circular, quadratic, and rational, whose frequencies are rotation sensitive. An analytical Tkachenko mode frequency from a hydrodynamic approach agrees well with that computed using BdG and Fourier analysis. The excitation spectrum remains symmetric around the angular quantum number $l=0$, but energy splitting between $l$ and $\ensuremath{-}l$ varies with the sign and strength of the nonlinear rotation. Finally, we demonstrate that the surface mode excitation frequency increases (decreases) with an increase in the positive (negative) nonlinear rotation strength.

Source: Physical Review A

DOI: 10.1103/99xp-w23f

Authors: Rony Boral, Swarup K. Sarkar, Matthew Edmonds, Paulsamy Muruganandam, Pankaj Kumar Mishra

Institutions: The University of Queensland, Keio University, Bharathidasan University

Language: English

Topic: Cold Atom Physics and Bose-Einstein Condensates

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green