Sound modes in collisional superfluid Bose gases

Year: 2021

Authors: Furutani K.; Tononi A.; Salasnich L.

Autors Affiliation: Dipartimento di Fisica e Astronomia ?Galileo Galilei?, Universita di Padova, via Marzolo 8, Padova, 35131, Italy; CNR-INO, via Nello Carrara, Sesto Fiorentino, 1-50019, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Padova, via Marzolo 8, Padova, 35131, Italy

Abstract: We theoretically investigate sound modes in a weakly-interacting collisional Bose gas in D dimensions. Using the Landau?s two-fluid hydrodynamics and working within the Bogoliubov theory, we observe the hybridization of the first and second sound modes for D >=2. To model the recent measurements of the sound velocities in 2D, obtained in the weakly-interacting regime and around the Berezinskii-Kosterlitz-Thouless transition temperature, we derive a refined calculation of the superfluid density, finding a fair agreement with the experiment. In the 1D case, for which experimental results are currently unavailable, we find no hybridization, triggering the necessity of future investigations. Our analysis provides a systematic understanding of sound propagation in a collisional weakly-interacting Bose gas in D dimensions.


Volume: 23 (4)      Pages from: 043043-1  to: 043043-10

More Information: We thank J Schmitt, M Ota, and V Singh for providing the experimental and theoretical data. We also acknowledge valuable comments from M Ota. KF acknowledges Fondazione Cassa di Risparmio di Padova e Rovigo for a PhD scholarship.
KeyWords: sound mode; Bose superfluid; Berezinski-Kosterlitz-Thouless transition
DOI: 10.1088/1367-2630/abed0c