Roton Excitations in an Oblate Dipolar Quantum Gas

We observe signatures of radial and angular roton excitations around a droplet crystallization transition in dipolar Bose-Einstein condensates. In situ measurements are used to characterize the density fluctuations near this transition. The static structure factor is extracted and used to identify t...

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Bibliographic Details
Published in:arXiv.org 2021-02
Main Authors: Schmidt, Jan-Niklas, Hertkorn, Jens, Guo, Mingyang, Böttcher, Fabian, Schmidt, Matthias, Ng, Kevin S H, Graham, Sean D, Langen, Tim, Zwierlein, Martin, Pfau, Tilman
Format: Article
Language:English
Subjects:
Bose-Einstein condensates
Crystallization
Excitation spectra
In situ measurement
Structure factor
Online Access:Get full text
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Summary:We observe signatures of radial and angular roton excitations around a droplet crystallization transition in dipolar Bose-Einstein condensates. In situ measurements are used to characterize the density fluctuations near this transition. The static structure factor is extracted and used to identify the radial and angular roton excitations by their characteristic symmetries. These fluctuations peak as a function of interaction strength indicating the crystallization transition of the system. We compare our observations to a theoretically calculated excitation spectrum allowing us to connect the crystallization mechanism with the softening of the angular roton modes.
ISSN:2331-8422
DOI:10.48550/arxiv.2102.01461