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Title
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Linear response of a superfluid Fermi gas inside its pair-breaking continuum
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Author
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Abstract
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| We study the signatures of the collective modes of a superfluid Fermi gas in its linear response functions for the order-parameter and density fluctuations in the Random Phase Approximation (RPA). We show that a resonance associated to the Popov-Andrianov (or sometimes "Higgs") mode is visible inside the pair-breaking continuum at all values of the wavevector q, not only in the (order-parameter) modulus-modulus response function but also in the modulus-density and density-density responses. At nonzero temperature, the resonance survives in the presence of thermally broken pairs even until the vicinity of the critical temperature T-c, and coexists with both the Anderson-Bogoliubov modes at temperatures comparable to the gap Delta and with the low-velocity phononic mode predicted by RPA near T-c. The existence of a Popov-Andrianov-"Higgs" resonance is thus a robust, generic feature of the high-energy phenomenology of pair-condensed Fermi gases, and should be accessible to state-of-the-art cold atom experiments. |
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Language
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English
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Source (journal)
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Scientific reports. - London, 2011, currens
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Publication
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London
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Nature Publishing Group
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2020
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ISSN
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2045-2322
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DOI
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10.1038/S41598-020-65371-9
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Volume/pages
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10
:1
(2020)
, 22 p.
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Article Reference
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11591
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ISI
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000550630600001
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Pubmed ID
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32665570
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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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