First and second sound in two-dimensional bosonic and fermionic superfluids

• Verfasst von: Salasnich, Luca [VerfasserIn]
• Verfasst von: Cappellaro, Alberto [VerfasserIn]
• Verfasst von: Furutani, Koichiro [VerfasserIn]
• Verfasst von: Tononi, Andrea [VerfasserIn]
• Verfasst von: Bighin, Giacomo [VerfasserIn]
• Titel: First and second sound in two-dimensional bosonic and fermionic superfluids
• Verf.angabe: Luca Salasnich, Alberto Cappellaro, Koichiro Furutani, Andrea Tononi and Giacomo Bighin
• E-Jahr: 2022
• Jahr: 17 October 2022
• Umfang: 10 S.
• Fussnoten: Gesehen am 29.11.2022
• Titel Quelle: Enthalten in: Symmetry
• Ort Quelle: Basel : MDPI, 2009
• Jahr Quelle: 2022
• Band/Heft Quelle: 14(2022), 10, Artikel-ID 2182, Seite 1-10
• ISSN Quelle: 2073-8994
• DOI: doi:10.3390/sym14102182
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: BCS-BEC crossover
• Sach-SW: superfluid bosons
• Sach-SW: superfluid fermions
• Sach-SW: two-dimensional systems
• K10plus-PPN: 1823830528

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 39K 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 6Li atoms. We also predict that there is mixing between sound modes only in the finite-temperature BEC regime.