Details
| Original language | English |
|---|---|
| Article number | 073024 |
| Number of pages | 10 |
| Journal | New journal of physics |
| Volume | 24 |
| Issue number | 7 |
| Publication status | Published - 1 Jul 2022 |
Abstract
We study the propagation of the two sound modes in two-dimensional Bose gases across the Berezinksii-Kosterlitz-Thouless transition using classical-field dynamics, which is motivated by recent measurements of Christodoulou et al (2021 Nature 594 191). Based on the dynamic structure factor (DSF), we identify the two sound modes as the Bogoliubov (B) and the non-Bogoliubov (NB) sound mode below the transition, and as the diffusive and the normal sound mode above the transition. The NB sound mode velocity is higher than the B sound mode velocity, which we refer to as the weak-coupling regime of the sound modes. We excite the sound modes by driving the system as in the experiment and by perturbing the density with a step-pulse perturbation, as a secondary comparison. The driven response depends on the driving strength and results in higher velocities for the B sound mode at high temperatures near the transition, compared to the sound results of the DSF and step-pulse excitation. We show that the higher mode velocity has a weak temperature dependence across the transition, which is consistent with the experimental observation.
Keywords
- Berezinksii-Kosterlitz-Thouless transition, collective modes, first and second sound, ultracold atom superfluids
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: New journal of physics, Vol. 24, No. 7, 073024, 01.07.2022.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - First and second sound in a dilute Bose gas across the BKT transition
AU - Singh, Vijay Pal
AU - Mathey, Ludwig
N1 - Funding Information: We thank Panagiotis Christodoulou for insightful discussions. This work is supported by the Deutsche Forschungsgemeinschaft (DFG) in the framework of SFB 925—Project ID 170620586 and the excellence cluster ‘Advanced Imaging of Matter’—EXC 2056—Project ID 390715994, and the Cluster of Excellence ‘QuantumFrontiers’—EXC 2123—Project ID 390837967.
PY - 2022/7/1
Y1 - 2022/7/1
N2 - We study the propagation of the two sound modes in two-dimensional Bose gases across the Berezinksii-Kosterlitz-Thouless transition using classical-field dynamics, which is motivated by recent measurements of Christodoulou et al (2021 Nature 594 191). Based on the dynamic structure factor (DSF), we identify the two sound modes as the Bogoliubov (B) and the non-Bogoliubov (NB) sound mode below the transition, and as the diffusive and the normal sound mode above the transition. The NB sound mode velocity is higher than the B sound mode velocity, which we refer to as the weak-coupling regime of the sound modes. We excite the sound modes by driving the system as in the experiment and by perturbing the density with a step-pulse perturbation, as a secondary comparison. The driven response depends on the driving strength and results in higher velocities for the B sound mode at high temperatures near the transition, compared to the sound results of the DSF and step-pulse excitation. We show that the higher mode velocity has a weak temperature dependence across the transition, which is consistent with the experimental observation.
AB - We study the propagation of the two sound modes in two-dimensional Bose gases across the Berezinksii-Kosterlitz-Thouless transition using classical-field dynamics, which is motivated by recent measurements of Christodoulou et al (2021 Nature 594 191). Based on the dynamic structure factor (DSF), we identify the two sound modes as the Bogoliubov (B) and the non-Bogoliubov (NB) sound mode below the transition, and as the diffusive and the normal sound mode above the transition. The NB sound mode velocity is higher than the B sound mode velocity, which we refer to as the weak-coupling regime of the sound modes. We excite the sound modes by driving the system as in the experiment and by perturbing the density with a step-pulse perturbation, as a secondary comparison. The driven response depends on the driving strength and results in higher velocities for the B sound mode at high temperatures near the transition, compared to the sound results of the DSF and step-pulse excitation. We show that the higher mode velocity has a weak temperature dependence across the transition, which is consistent with the experimental observation.
KW - Berezinksii-Kosterlitz-Thouless transition
KW - collective modes
KW - first and second sound
KW - ultracold atom superfluids
UR - http://www.scopus.com/inward/record.url?scp=85136592602&partnerID=8YFLogxK
U2 - 10.48550/arXiv.2203.08837
DO - 10.48550/arXiv.2203.08837
M3 - Article
AN - SCOPUS:85136592602
VL - 24
JO - New journal of physics
JF - New journal of physics
SN - 1367-2630
IS - 7
M1 - 073024
ER -