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  • Letter
  • Open Access

Probing the BCS-BEC crossover with persistent currents

Giovanni Pecci1, Piero Naldesi1, Luigi Amico2,3,4,5, and Anna Minguzzi1

  • 1Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
  • 2Quantum Research Centre, Technology Innovation Institute, P.O. Box 9639, Abu Dhabi, United Arab Emirates
  • 3CNR-IMM and INFN-Sezione di Catania, Via S. Sofia 64, 95127 Catania, Italy
  • 4Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
  • 5LANEF Chaire d'Excellence, Université Grenoble-Alpes and CNRS, F-38000 Grenoble, France

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Phys. Rev. Research 3, L032064 – Published 14 September, 2021

DOI: https://doi.org/10.1103/PhysRevResearch.3.L032064

Abstract

We study the persistent currents of an attractive Fermi gas confined in a tightly confining ring trap and subjected to an artificial gauge field all through the BCS-BEC crossover. At weak attractions, on the Bardeen-Cooper-Schrieffer (BCS) side, fermions display a parity effect in the persistent currents, i.e., their response to the gauge field is paramagnetic or diamagnetic depending on the number of pairs on the ring. At resonance and on the Bose-Einstein condensate (BEC) side of the crossover we find a doubling of the periodicity of the ground-state energy as a function of the artificial gauge field and disappearance of the parity effect, indicating that persistent currents can be used to infer the formation of tightly bound bosonic pairs. Our predictions can be accessed in ultracold atom experiments through noise interferograms.

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Phys. Rev. Research 3, L032064– Published 14 September, 2021
  • Received 13 October 2020
  • Accepted 9 July 2021
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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