Vortices in a two-dimensional fermionic superfluid
Abstract
Quantized vortices are a hallmark of superfluidity. They have proven to be an indispensable probe for systems ranging from superfluid helium to type-II superconductors. In ultracold two-dimensional (2D) Fermi gases, where phase fluctuations are enhanced and the Berezinskii-Kosterlitz-Thouless (BKT) mechanism governs the superfluid transition, their observation has remained elusive. Here, we report on the controlled creation of quantized vortices in a homogeneous 2D gas in the BEC--BCS crossover. By continuously tuning the velocity of two moving obstacles, we observe quantized steps in the absolute vortex charge. Matter-wave interferometry reveals the characteristic phase winding, quantized in units of 2π. Measurements on 2D and 3D gases show a striking difference: only in 2D does the vortex number grow with temperature, reflecting thermal activation of BKT vortex pairs. Our approach provides evidence of fermionic superfluidity in 2D and offers a means to study BKT physics, vortex-controlled transport and resistance, as well as to detect unconventional superfluidity in spin-imbalanced 2D gases.
Related
- Minimal superfluid vortices in chiral perturbation theory
- Emergent Conformal Symmetry on Superfluid Vortices in Two-Color QCD and Pseudoreal Gauge Theories
- Fractional Superfluid Vortices and Worldsheet Wess--Zumino--Witten Models in Two-Color QCD and Sp(2N) Gauge Theories
- Splitting Dynamics of Multiply Quantized Vortices in Holographic Superfluid of Finite Temperature
- Fermionic superfluid transition and pairing scale separation in the kagome flat band
BibTeX
@misc{mkrtchyan2026vortices,
title = {{Vortices in a two-dimensional fermionic superfluid}},
author = {Artak Mkrtchyan and Hans Leonard Michel and Moritz von Usslar and René Henke and Cesar Raymundo Cabrera and Henning Moritz},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.05017},
eprint = {2611.05017},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.05017},
}
RIS
TY - UNPB
TI - Vortices in a two-dimensional fermionic superfluid
AU - Artak Mkrtchyan
AU - Hans Leonard Michel
AU - Moritz von Usslar
AU - René Henke
AU - Cesar Raymundo Cabrera
AU - Henning Moritz
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.05017
UR - https://arxiv.org/abs/2611.05017
AB - Quantized vortices are a hallmark of superfluidity. They have proven to be an indispensable probe for systems ranging from superfluid helium to type-II superconductors. In ultracold two-dimensional (2D) Fermi gases, where phase fluctuations are enhanced and the Berezinskii-Kosterlitz-Thouless (BKT) mechanism governs the superfluid transition, their observation has remained elusive. Here, we report on the controlled creation of quantized vortices in a homogeneous 2D gas in the BEC--BCS crossover. By continuously tuning the velocity of two moving obstacles, we observe quantized steps in the absolute vortex charge. Matter-wave interferometry reveals the characteristic phase winding, quantized in units of 2π. Measurements on 2D and 3D gases show a striking difference: only in 2D does the vortex number grow with temperature, reflecting thermal activation of BKT vortex pairs. Our approach provides evidence of fermionic superfluidity in 2D and offers a means to study BKT physics, vortex-controlled transport and resistance, as well as to detect unconventional superfluidity in spin-imbalanced 2D gases.
ER -