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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2408.00446 |
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| _version_ | 1866929743601860608 |
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| author | Kawamura, Taira Ohashi, Yoji |
| author_facet | Kawamura, Taira Ohashi, Yoji |
| contents | We present a theoretical review of the recent progress in nonequilibrium BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover physics. As a paradigmatic example, we consider a strongly interacting driven-dissipative two-component Fermi gas where the nonequilibrium steady state is tuned by adjusting the chemical potential difference between two reservoirs that are coupled with the system. As a powerful theoretical tool to deal with this system, we employ the Schwinger-Keldysh Green's function technique. We systematically evaluate the superfluid transition, as well as the single-particle properties, in the nonequilibrium BCS-BEC crossover region, by adjusting the chemical potential difference between the reservoirs and the strength of an s-wave pairing interaction associated with a Feshbach resonance. In the weak-coupling BCS side, the chemical potential difference is shown to imprint a two-step structure on the particle momentum distribution, leading to an anomalous enhancement of pseudogap, as well as the emergence of exotic Fulde-Ferrell-Larkin-Ovchinnikov-type superfluid instability. Since various nonequilibrium situations have recently been realized in ultracold Fermi gases, the theoretical understanding of nonequilibrium BCS-BEC crossover physics would become increasingly important in this research field. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_00446 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Nonequilibrium BCS-BEC crossover and unconventional FFLO superfluid in a strongly interacting driven-dissipative Fermi gas Kawamura, Taira Ohashi, Yoji Quantum Gases We present a theoretical review of the recent progress in nonequilibrium BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover physics. As a paradigmatic example, we consider a strongly interacting driven-dissipative two-component Fermi gas where the nonequilibrium steady state is tuned by adjusting the chemical potential difference between two reservoirs that are coupled with the system. As a powerful theoretical tool to deal with this system, we employ the Schwinger-Keldysh Green's function technique. We systematically evaluate the superfluid transition, as well as the single-particle properties, in the nonequilibrium BCS-BEC crossover region, by adjusting the chemical potential difference between the reservoirs and the strength of an s-wave pairing interaction associated with a Feshbach resonance. In the weak-coupling BCS side, the chemical potential difference is shown to imprint a two-step structure on the particle momentum distribution, leading to an anomalous enhancement of pseudogap, as well as the emergence of exotic Fulde-Ferrell-Larkin-Ovchinnikov-type superfluid instability. Since various nonequilibrium situations have recently been realized in ultracold Fermi gases, the theoretical understanding of nonequilibrium BCS-BEC crossover physics would become increasingly important in this research field. |
| title | Nonequilibrium BCS-BEC crossover and unconventional FFLO superfluid in a strongly interacting driven-dissipative Fermi gas |
| topic | Quantum Gases |
| url | https://arxiv.org/abs/2408.00446 |