---
_id: '9606'
abstract:
- lang: eng
text: Sound propagation is a macroscopic manifestation of the interplay between
the equilibrium thermodynamics and the dynamical transport properties of fluids.
Here, for a two-dimensional system of ultracold fermions, we calculate the first
and second sound velocities across the whole BCS-BEC crossover, and we analyze
the system response to an external perturbation. In the low-temperature regime
we reproduce the recent measurements [Phys. Rev. Lett. 124, 240403 (2020)] of
the first sound velocity, which, due to the decoupling of density and entropy
fluctuations, is the sole mode excited by a density probe. Conversely, a heat
perturbation excites only the second sound, which, being sensitive to the superfluid
depletion, vanishes in the deep BCS regime and jumps discontinuously to zero at
the Berezinskii-Kosterlitz-Thouless superfluid transition. A mixing between the
modes occurs only in the finite-temperature BEC regime, where our theory converges
to the purely bosonic results.
acknowledgement: "G.B. acknowledges support from the Austrian Science Fund (FWF),
under Project No. M2641-N27. This work was\r\npartially supported by the University
of Padua, BIRD project “Superfluid properties of Fermi gases in optical potentials.”\r\nThe
authors thank Miki Ota, Tomoki Ozawa, Sandro Stringari, Tilman Enss, Hauke Biss,
Henning Moritz, and Nicolò Defenu for fruitful discussions. The authors thank Henning
Moritz and Markus Bohlen for providing their experimental\r\ndata."
article_number: L061303
article_processing_charge: No
article_type: letter_note
author:
- first_name: A.
full_name: Tononi, A.
last_name: Tononi
- first_name: Alberto
full_name: Cappellaro, Alberto
id: 9d13b3cb-30a2-11eb-80dc-f772505e8660
last_name: Cappellaro
orcid: 0000-0001-6110-2359
- first_name: Giacomo
full_name: Bighin, Giacomo
id: 4CA96FD4-F248-11E8-B48F-1D18A9856A87
last_name: Bighin
orcid: 0000-0001-8823-9777
- first_name: L.
full_name: Salasnich, L.
last_name: Salasnich
citation:
ama: Tononi A, Cappellaro A, Bighin G, Salasnich L. Propagation of first and second
sound in a two-dimensional Fermi superfluid. Physical Review A. 2021;103(6).
doi:10.1103/PhysRevA.103.L061303
apa: Tononi, A., Cappellaro, A., Bighin, G., & Salasnich, L. (2021). Propagation
of first and second sound in a two-dimensional Fermi superfluid. Physical Review
A. American Physical Society. https://doi.org/10.1103/PhysRevA.103.L061303
chicago: Tononi, A., Alberto Cappellaro, Giacomo Bighin, and L. Salasnich. “Propagation
of First and Second Sound in a Two-Dimensional Fermi Superfluid.” Physical
Review A. American Physical Society, 2021. https://doi.org/10.1103/PhysRevA.103.L061303.
ieee: A. Tononi, A. Cappellaro, G. Bighin, and L. Salasnich, “Propagation of first
and second sound in a two-dimensional Fermi superfluid,” Physical Review A,
vol. 103, no. 6. American Physical Society, 2021.
ista: Tononi A, Cappellaro A, Bighin G, Salasnich L. 2021. Propagation of first
and second sound in a two-dimensional Fermi superfluid. Physical Review A. 103(6),
L061303.
mla: Tononi, A., et al. “Propagation of First and Second Sound in a Two-Dimensional
Fermi Superfluid.” Physical Review A, vol. 103, no. 6, L061303, American
Physical Society, 2021, doi:10.1103/PhysRevA.103.L061303.
short: A. Tononi, A. Cappellaro, G. Bighin, L. Salasnich, Physical Review A 103
(2021).
date_created: 2021-06-27T22:01:49Z
date_published: 2021-06-01T00:00:00Z
date_updated: 2023-08-10T13:37:25Z
day: '01'
department:
- _id: MiLe
doi: 10.1103/PhysRevA.103.L061303
external_id:
arxiv:
- '2009.06491'
isi:
- '000662296700014'
intvolume: ' 103'
isi: 1
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2009.06491
month: '06'
oa: 1
oa_version: Preprint
publication: Physical Review A
publication_identifier:
eissn:
- '24699934'
issn:
- '24699926'
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Propagation of first and second sound in a two-dimensional Fermi superfluid
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 103
year: '2021'
...
---
_id: '8319'
abstract:
- lang: eng
text: We demonstrate that releasing atoms into free space from an optical lattice
does not deteriorate cavity-generated spin squeezing for metrological purposes.
In this work, an ensemble of 500000 spin-squeezed atoms in a high-finesse optical
cavity with near-uniform atom-cavity coupling is prepared, released into free
space, recaptured in the cavity, and probed. Up to ∼10 dB of metrologically relevant
squeezing is retrieved for 700μs free-fall times, and decaying levels of squeezing
are realized for up to 3 ms free-fall times. The degradation of squeezing results
from loss of atom-cavity coupling homogeneity between the initial squeezed state
generation and final collective state readout. A theoretical model is developed
to quantify this degradation and this model is experimentally validated.
acknowledgement: We thank N. Engelsen for comments on the manuscript. This work was
supported by the Office of Naval Research, Vannevar Bush Faculty Fellowship, Department
of Energy, and Defense Threat Reduction Agency. R.K. was partly supported by the
AQT/INQNET program at Caltech.
article_number: '012224'
article_processing_charge: No
article_type: original
author:
- first_name: Yunfan
full_name: Wu, Yunfan
last_name: Wu
- first_name: Rajiv
full_name: Krishnakumar, Rajiv
last_name: Krishnakumar
- first_name: Julián
full_name: Martínez-Rincón, Julián
last_name: Martínez-Rincón
- first_name: Benjamin K.
full_name: Malia, Benjamin K.
last_name: Malia
- first_name: Onur
full_name: Hosten, Onur
id: 4C02D85E-F248-11E8-B48F-1D18A9856A87
last_name: Hosten
orcid: 0000-0002-2031-204X
- first_name: Mark A.
full_name: Kasevich, Mark A.
last_name: Kasevich
citation:
ama: Wu Y, Krishnakumar R, Martínez-Rincón J, Malia BK, Hosten O, Kasevich MA. Retrieval
of cavity-generated atomic spin squeezing after free-space release. Physical
Review A. 2020;102(1). doi:10.1103/PhysRevA.102.012224
apa: Wu, Y., Krishnakumar, R., Martínez-Rincón, J., Malia, B. K., Hosten, O., &
Kasevich, M. A. (2020). Retrieval of cavity-generated atomic spin squeezing after
free-space release. Physical Review A. American Physical Society. https://doi.org/10.1103/PhysRevA.102.012224
chicago: Wu, Yunfan, Rajiv Krishnakumar, Julián Martínez-Rincón, Benjamin K. Malia,
Onur Hosten, and Mark A. Kasevich. “Retrieval of Cavity-Generated Atomic Spin
Squeezing after Free-Space Release.” Physical Review A. American Physical
Society, 2020. https://doi.org/10.1103/PhysRevA.102.012224.
ieee: Y. Wu, R. Krishnakumar, J. Martínez-Rincón, B. K. Malia, O. Hosten, and M.
A. Kasevich, “Retrieval of cavity-generated atomic spin squeezing after free-space
release,” Physical Review A, vol. 102, no. 1. American Physical Society,
2020.
ista: Wu Y, Krishnakumar R, Martínez-Rincón J, Malia BK, Hosten O, Kasevich MA.
2020. Retrieval of cavity-generated atomic spin squeezing after free-space release.
Physical Review A. 102(1), 012224.
mla: Wu, Yunfan, et al. “Retrieval of Cavity-Generated Atomic Spin Squeezing after
Free-Space Release.” Physical Review A, vol. 102, no. 1, 012224, American
Physical Society, 2020, doi:10.1103/PhysRevA.102.012224.
short: Y. Wu, R. Krishnakumar, J. Martínez-Rincón, B.K. Malia, O. Hosten, M.A. Kasevich,
Physical Review A 102 (2020).
date_created: 2020-08-30T22:01:10Z
date_published: 2020-07-30T00:00:00Z
date_updated: 2024-02-28T13:11:28Z
day: '30'
department:
- _id: OnHo
doi: 10.1103/PhysRevA.102.012224
external_id:
arxiv:
- '1912.08334'
isi:
- '000555104200011'
intvolume: ' 102'
isi: 1
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1912.08334
month: '07'
oa: 1
oa_version: Preprint
publication: Physical Review A
publication_identifier:
eissn:
- '24699934'
issn:
- '24699926'
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Retrieval of cavity-generated atomic spin squeezing after free-space release
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 102
year: '2020'
...
---
_id: '6632'
abstract:
- lang: eng
text: We consider a two-component Bose gas in two dimensions at a low temperature
with short-range repulsive interaction. In the coexistence phase where both components
are superfluid, interspecies interactions induce a nondissipative drag between
the two superfluid flows (Andreev-Bashkin effect). We show that this behavior
leads to a modification of the usual Berezinskii-Kosterlitz-Thouless (BKT) transition
in two dimensions. We extend the renormalization of the superfluid densities at
finite temperature using the renormalization-group approach and find that the
vortices of one component have a large influence on the superfluid properties
of the other, mediated by the nondissipative drag. The extended BKT flow equations indicate that the occurrence of the
vortex unbinding transition in one of the components can induce the breakdown
of superfluidity also in the other, leading to a locking phenomenon for the critical
temperatures of the two gases.
article_number: '063627'
article_processing_charge: No
author:
- first_name: Volker
full_name: Karle, Volker
last_name: Karle
- first_name: Nicolò
full_name: Defenu, Nicolò
last_name: Defenu
- first_name: Tilman
full_name: Enss, Tilman
last_name: Enss
citation:
ama: Karle V, Defenu N, Enss T. Coupled superfluidity of binary Bose mixtures in
two dimensions. Physical Review A. 2019;99(6). doi:10.1103/PhysRevA.99.063627
apa: Karle, V., Defenu, N., & Enss, T. (2019). Coupled superfluidity of binary
Bose mixtures in two dimensions. Physical Review A. American Physical Society.
https://doi.org/10.1103/PhysRevA.99.063627
chicago: Karle, Volker, Nicolò Defenu, and Tilman Enss. “Coupled Superfluidity of
Binary Bose Mixtures in Two Dimensions.” Physical Review A. American Physical
Society, 2019. https://doi.org/10.1103/PhysRevA.99.063627.
ieee: V. Karle, N. Defenu, and T. Enss, “Coupled superfluidity of binary Bose mixtures
in two dimensions,” Physical Review A, vol. 99, no. 6. American Physical
Society, 2019.
ista: Karle V, Defenu N, Enss T. 2019. Coupled superfluidity of binary Bose mixtures
in two dimensions. Physical Review A. 99(6), 063627.
mla: Karle, Volker, et al. “Coupled Superfluidity of Binary Bose Mixtures in Two
Dimensions.” Physical Review A, vol. 99, no. 6, 063627, American Physical
Society, 2019, doi:10.1103/PhysRevA.99.063627.
short: V. Karle, N. Defenu, T. Enss, Physical Review A 99 (2019).
date_created: 2019-07-14T21:59:17Z
date_published: 2019-06-28T00:00:00Z
date_updated: 2024-02-28T13:12:34Z
day: '28'
department:
- _id: MiLe
doi: 10.1103/PhysRevA.99.063627
external_id:
arxiv:
- '1903.06759'
isi:
- '000473133600007'
intvolume: ' 99'
isi: 1
issue: '6'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/1903.06759
month: '06'
oa: 1
oa_version: Preprint
publication: Physical Review A
publication_identifier:
eissn:
- '24699934'
issn:
- '24699926'
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Coupled superfluidity of binary Bose mixtures in two dimensions
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 99
year: '2019'
...