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Main Authors: Tomishiyo, Guilherme, Madeira, Lucas, Caracanhas, Mônica A.
Format: Preprint
Published: 2022
Subjects:
Online Access:https://arxiv.org/abs/2212.11027
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author Tomishiyo, Guilherme
Madeira, Lucas
Caracanhas, Mônica A.
author_facet Tomishiyo, Guilherme
Madeira, Lucas
Caracanhas, Mônica A.
contents We studied a rotating Bose-Einstein condensate confined in ring trap configurations that can be produced starting with a bubble trap confinement, approximated by a Mexican hat and shifted harmonic oscillator potentials. Using a variational technique and perturbation theory, we determined the vortex configurations in this system by varying the interparticle interaction and the angular velocity of the atomic cloud. We found that the phase diagram of the system has macrovortex structures for small positive values of the interaction parameter, and the charge of the central vortex increases with rotation. Strengthening the atomic interaction makes the macrovortex unstable, and it decays into multiple singly-charged vortices that arrange themselves in a lattice configuration. We also look for experimentally realizable methods to determine the vortex configuration without relying upon absorption imaging since the structures are not always visible in the latter. More specifically, we study how the vortex distribution affects the collective modes of the condensate by solving the Gross-Pitaevskii equation numerically and by analytical predictions using the sum-rule approach for the frequencies of the modes. These results reveal important signatures to characterize the macrovortices and vortex lattice transitions in the experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2212_11027
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Superfluid excitations in rotating two-dimensional ring traps
Tomishiyo, Guilherme
Madeira, Lucas
Caracanhas, Mônica A.
Quantum Gases
We studied a rotating Bose-Einstein condensate confined in ring trap configurations that can be produced starting with a bubble trap confinement, approximated by a Mexican hat and shifted harmonic oscillator potentials. Using a variational technique and perturbation theory, we determined the vortex configurations in this system by varying the interparticle interaction and the angular velocity of the atomic cloud. We found that the phase diagram of the system has macrovortex structures for small positive values of the interaction parameter, and the charge of the central vortex increases with rotation. Strengthening the atomic interaction makes the macrovortex unstable, and it decays into multiple singly-charged vortices that arrange themselves in a lattice configuration. We also look for experimentally realizable methods to determine the vortex configuration without relying upon absorption imaging since the structures are not always visible in the latter. More specifically, we study how the vortex distribution affects the collective modes of the condensate by solving the Gross-Pitaevskii equation numerically and by analytical predictions using the sum-rule approach for the frequencies of the modes. These results reveal important signatures to characterize the macrovortices and vortex lattice transitions in the experiments.
title Superfluid excitations in rotating two-dimensional ring traps
topic Quantum Gases
url https://arxiv.org/abs/2212.11027