Hybrid-pair superfluidity in a strongly driven Fermi gas

Fuente: arXiv
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Main Authors: Mulkerin, Brendan C., Bleu, Olivier, Cabrera, Cesar R., Parish, Meera M., Levinsen, Jesper
Format: Preprint
Published: 2025
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_version_ 1866911215601582080
author Mulkerin, Brendan C.
Bleu, Olivier
Cabrera, Cesar R.
Parish, Meera M.
Levinsen, Jesper
author_facet Mulkerin, Brendan C.
Bleu, Olivier
Cabrera, Cesar R.
Parish, Meera M.
Levinsen, Jesper
contents We explore the paired superfluid phases of a Fermi gas in the presence of a continuous Rabi drive. We focus on the case where two components are strongly coupled by the drive, forming hybrid superpositions, and interacting with an uncoupled third component. Using a generalized Bardeen- Cooper-Schrieffer (BCS) ansatz, we show that there are two coupled superfluid order parameters, and we obtain the associated free energy and quasiparticle excitation spectrum. We find that we can drive BCS-BCS, BCS-Bose-Einstein condensate (BEC) and BEC-BEC crossovers purely by varying the detuning of the Rabi drive from the bare transition, with the precise crossover depending on the sign of the underlying interactions between the coupled and uncoupled components. We furthermore identify an exotic excited branch which features both normal to BCS superfluid transitions, as well as a BCS-BEC-BCS crossover. Introducing a generalized Thouless criterion, we show that this behavior is reflected in the critical temperature for superfluidity. Our Rabi-coupled scenario also gives possesses additional thermodynamic properties related to the pseudospin of the coupled components, which provide novel signatures of the state of the many-body system. The Rabi-driven Fermi gas thus emerges as a unique platform for engineering and probing a rich array of multi-band superfluid phases.
format Preprint
id arxiv_https___arxiv_org_abs_2503_10980
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid-pair superfluidity in a strongly driven Fermi gas
Mulkerin, Brendan C.
Bleu, Olivier
Cabrera, Cesar R.
Parish, Meera M.
Levinsen, Jesper
Quantum Gases
We explore the paired superfluid phases of a Fermi gas in the presence of a continuous Rabi drive. We focus on the case where two components are strongly coupled by the drive, forming hybrid superpositions, and interacting with an uncoupled third component. Using a generalized Bardeen- Cooper-Schrieffer (BCS) ansatz, we show that there are two coupled superfluid order parameters, and we obtain the associated free energy and quasiparticle excitation spectrum. We find that we can drive BCS-BCS, BCS-Bose-Einstein condensate (BEC) and BEC-BEC crossovers purely by varying the detuning of the Rabi drive from the bare transition, with the precise crossover depending on the sign of the underlying interactions between the coupled and uncoupled components. We furthermore identify an exotic excited branch which features both normal to BCS superfluid transitions, as well as a BCS-BEC-BCS crossover. Introducing a generalized Thouless criterion, we show that this behavior is reflected in the critical temperature for superfluidity. Our Rabi-coupled scenario also gives possesses additional thermodynamic properties related to the pseudospin of the coupled components, which provide novel signatures of the state of the many-body system. The Rabi-driven Fermi gas thus emerges as a unique platform for engineering and probing a rich array of multi-band superfluid phases.
title Hybrid-pair superfluidity in a strongly driven Fermi gas
topic Quantum Gases
url https://arxiv.org/abs/2503.10980