First and Second Sound in Two-Dimensional Bosonic and Fermionic Superfluids
Year: 2022
Authors: Salasnich L., Cappellaro A., Furutani K., Tononi A., Bighin G.
Autors Affiliation: Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Via Marzolo 8, I-35131 Padua, Italy; Univ Padua, Padua QTech, Via Marzolo 8, I-35131 Padua, Italy; Consiglio Nazl Ric CNR, Ist Nazl Ott INO, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy; Ist Nazl Fis Nucl INFN, Sez Padova, Via Marzolo 8, I-35131 Padua, Italy; Inst Sci & Technol Austria ISTA, Campus 1, A-3400 Klosterneuburg, Austria; Univ Paris Saclay, French Natl Ctr Sci Res CNRS, Lab Theoret Phys & Stat Models LPTMS, F-91405 Orsay, France; Heidelberg Univ, Inst Theoret Phys, Philosophenweg 19, D-69120 Heidelberg, Germany.
Abstract: We review our theoretical results of the sound propagation in two-dimensional (2D) systems of ultracold fermionic and bosonic atoms. In the superfluid phase, characterized by the spontaneous symmetry breaking of the U(1) symmetry, there is the coexistence of first and second sound. In the case of weakly-interacting repulsive bosons, we model the recent measurements of the sound velocities of K-39 atoms in 2D obtained in the weakly-interacting regime and around the Berezinskii-Kosterlitz-Thouless (BKT) superfluid-to-normal transition temperature. In particular, we perform a quite accurate computation of the superfluid density and show that it is reasonably consistent with the experimental results. For superfluid attractive fermions, we calculate the first and second sound velocities across the whole BCS-BEC crossover. In the low-temperature regime, we reproduce the recent measurements of first-sound speed with Li-6 atoms. We also predict that there is mixing between sound modes only in the finite-temperature BEC regime.
Journal/Review: Symmetry-Basel
Volume: 14 (10) Pages from: 2182-1 to: 2182-10
More Information: This research is partially supported by University of Padova, BIRD grant Ultracold atoms in curved geometries. KF is supported by Fondazione CARIPARO with a PhD fellowship. AT is partially supported by French National Research Agency ANR Grant Droplets N. ANR-19-CE30-0003-02.KeyWords: two-dimensional systems; superfluid bosons; superfluid fermions; BCS-BEC crossoverDOI: 10.3390/sym14102182Citations: 1data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2025-01-12References taken from IsiWeb of Knowledge: (subscribers only)