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Title
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Leggett collective excitations in a two-band Fermi superfluid at finite temperatures
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Author
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Abstract
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| The Leggett collective excitations for a two-band Fermi gas with s-wave pairing and Josephson interband coupling in the BCS-BEC crossover at finite temperatures are investigated within the Gaussian pair fluctuation approach. Eigenfrequencies and damping factors for Leggett modes are determined in a nonperturbative way, using the analytic continuation of the fluctuation propagator through a branch cut in the complex frequency plane, as in Kurkjian et al (2019 Phys. Rev. Lett. 122 093403). The treatment is performed beyond the low-energy expansion, which is necessary when the collective excitation energy reaches the pair-breaking continuum edge. The results are applied in particular to cold atomic gases at the orbital Feshbach resonance and in a regime far from BEC, which can be relevant for future experiments. |
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Language
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English
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Source (journal)
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New journal of physics / Institute of Physics [Londen]; German Physical Society. - Bristol
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Publication
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Bristol
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2019
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ISSN
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1367-2630
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DOI
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10.1088/1367-2630/AB54B0
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Volume/pages
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21
:11
(2019)
, 14 p.
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Article Reference
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113043
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ISI
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000498853200001
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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