---
_id: '12154'
abstract:
- lang: eng
  text: 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.
acknowledgement: "This research is partially supported by University of Padova, BIRD
  grant “Ultracold atoms\r\nin curved geometries”. KF is supported by Fondazione CARIPARO
  with a PhD fellowship. AT is\r\npartially supported by French National Research
  Agency ANR Grant Droplets N. ANR-19-CE30-0003-02. LS thanks Herwig Ott and Sandro
  Wimberger for their kind invitation to the\r\nInternational Workshop “Quantum Transport
  with ultracold atoms” (2022)."
article_number: '2182'
article_processing_charge: Yes
article_type: original
author:
- first_name: Luca
  full_name: Salasnich, Luca
  last_name: Salasnich
- first_name: Alberto
  full_name: Cappellaro, Alberto
  id: 9d13b3cb-30a2-11eb-80dc-f772505e8660
  last_name: Cappellaro
  orcid: 0000-0001-6110-2359
- first_name: Koichiro
  full_name: Furutani, Koichiro
  last_name: Furutani
- first_name: Andrea
  full_name: Tononi, Andrea
  last_name: Tononi
- first_name: Giacomo
  full_name: Bighin, Giacomo
  id: 4CA96FD4-F248-11E8-B48F-1D18A9856A87
  last_name: Bighin
  orcid: 0000-0001-8823-9777
citation:
  ama: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. First and second
    sound in two-dimensional bosonic and fermionic superfluids. <i>Symmetry</i>. 2022;14(10).
    doi:<a href="https://doi.org/10.3390/sym14102182">10.3390/sym14102182</a>
  apa: Salasnich, L., Cappellaro, A., Furutani, K., Tononi, A., &#38; Bighin, G. (2022).
    First and second sound in two-dimensional bosonic and fermionic superfluids. <i>Symmetry</i>.
    MDPI. <a href="https://doi.org/10.3390/sym14102182">https://doi.org/10.3390/sym14102182</a>
  chicago: Salasnich, Luca, Alberto Cappellaro, Koichiro Furutani, Andrea Tononi,
    and Giacomo Bighin. “First and Second Sound in Two-Dimensional Bosonic and Fermionic
    Superfluids.” <i>Symmetry</i>. MDPI, 2022. <a href="https://doi.org/10.3390/sym14102182">https://doi.org/10.3390/sym14102182</a>.
  ieee: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, and G. Bighin, “First
    and second sound in two-dimensional bosonic and fermionic superfluids,” <i>Symmetry</i>,
    vol. 14, no. 10. MDPI, 2022.
  ista: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. 2022. First and
    second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. 14(10),
    2182.
  mla: Salasnich, Luca, et al. “First and Second Sound in Two-Dimensional Bosonic
    and Fermionic Superfluids.” <i>Symmetry</i>, vol. 14, no. 10, 2182, MDPI, 2022,
    doi:<a href="https://doi.org/10.3390/sym14102182">10.3390/sym14102182</a>.
  short: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, G. Bighin, Symmetry
    14 (2022).
date_created: 2023-01-12T12:08:31Z
date_published: 2022-10-17T00:00:00Z
date_updated: 2023-08-09T10:13:17Z
day: '17'
ddc:
- '530'
department:
- _id: MiLe
doi: 10.3390/sym14102182
external_id:
  isi:
  - '000875039200001'
file:
- access_level: open_access
  checksum: 9b6bd0e484834dd76d7b26e3c5fba8bd
  content_type: application/pdf
  creator: dernst
  date_created: 2023-01-24T10:56:12Z
  date_updated: 2023-01-24T10:56:12Z
  file_id: '12361'
  file_name: 2022_Symmetry_Salsnich.pdf
  file_size: 843723
  relation: main_file
  success: 1
file_date_updated: 2023-01-24T10:56:12Z
has_accepted_license: '1'
intvolume: '        14'
isi: 1
issue: '10'
keyword:
- Physics and Astronomy (miscellaneous)
- General Mathematics
- Chemistry (miscellaneous)
- Computer Science (miscellaneous)
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
publication: Symmetry
publication_identifier:
  issn:
  - 2073-8994
publication_status: published
publisher: MDPI
quality_controlled: '1'
scopus_import: '1'
status: public
title: First and second sound in two-dimensional bosonic and fermionic superfluids
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 14
year: '2022'
...