Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas

doi:https://doi.org/10.1103/PHYSREVA.82.043630

Title: Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas

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Abstract

We investigate single-particle excitations and strong-coupling effects in the BCS-BEC crossover regime of a superfluid Fermi gas. Including phase and amplitude fluctuations of the superfluid order parameter within a T-matrix theory, we calculate the superfluid density of states (DOS), as well as single-particle spectral weight, over the entire BCS-BEC crossover region below the superfluid transition temperature T{sub c}. We clarify how the pseudogap in the normal state evolves into the superfluid gap, as one passes through T{sub c}. While the pseudogap in DOS continuously evolves into the superfluid gap in the weak-coupling BCS regime, the superfluid gap in the crossover region is shown to appear in DOS after the pseudogap disappears below T{sub c}. In the phase diagram with respect to the temperature and interaction strength, we determine the region where strong pairing fluctuations dominate over single-particle properties of the system. Our results would be useful for the study of strong-coupling phenomena in the BCS-BEC crossover regime of a superfluid Fermi gas.

Authors:

Watanabe, Ryota ^[1]; Tsuchiya, Shunji ^[2]; Ohashi, Yoji ^[1]

Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)
Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

Publication Date:: 2010-10-15

OSTI Identifier:: 21454817

Resource Type:: Journal Article

Journal Name:: Physical Review. A

Additional Journal Information:: Journal Volume: 82; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.82.043630; (c) 2010 The American Physical Society; Journal ID: ISSN 1050-2947

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMPLITUDES; BCS THEORY; BOSE-EINSTEIN CONDENSATION; COUPLING; ENERGY GAP; ENERGY-LEVEL DENSITY; EXCITATION; FERMI GAS; FLUCTUATIONS; ORDER PARAMETERS; PAIRING INTERACTIONS; PHASE DIAGRAMS; S MATRIX; SINGLE-PARTICLE MODES; SUPERFLUIDITY; TRANSITION TEMPERATURE; DIAGRAMS; DIMENSIONLESS NUMBERS; ENERGY-LEVEL TRANSITIONS; INFORMATION; INTERACTIONS; MATRICES; OSCILLATION MODES; PHYSICAL PROPERTIES; THERMODYNAMIC PROPERTIES; VARIATIONS

Citation Formats


                    Watanabe, Ryota, Tsuchiya, Shunji, CREST, Ohashi, Yoji, and CREST. Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas.  United States: N. p., 2010. 
        Web.  doi:10.1103/PHYSREVA.82.043630.

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                    Watanabe, Ryota, Tsuchiya, Shunji, CREST, Ohashi, Yoji, & CREST. Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas.  United States.  https://doi.org/10.1103/PHYSREVA.82.043630

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                    Watanabe, Ryota, Tsuchiya, Shunji, CREST, Ohashi, Yoji, and CREST. Fri .  
        "Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas".  United States.  https://doi.org/10.1103/PHYSREVA.82.043630.

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@article{osti_21454817,

  title        = {Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas},

  author       = {Watanabe, Ryota and Tsuchiya, Shunji and CREST and Ohashi, Yoji and CREST},

  abstractNote = {We investigate single-particle excitations and strong-coupling effects in the BCS-BEC crossover regime of a superfluid Fermi gas. Including phase and amplitude fluctuations of the superfluid order parameter within a T-matrix theory, we calculate the superfluid density of states (DOS), as well as single-particle spectral weight, over the entire BCS-BEC crossover region below the superfluid transition temperature T{sub c}. We clarify how the pseudogap in the normal state evolves into the superfluid gap, as one passes through T{sub c}. While the pseudogap in DOS continuously evolves into the superfluid gap in the weak-coupling BCS regime, the superfluid gap in the crossover region is shown to appear in DOS after the pseudogap disappears below T{sub c}. In the phase diagram with respect to the temperature and interaction strength, we determine the region where strong pairing fluctuations dominate over single-particle properties of the system. Our results would be useful for the study of strong-coupling phenomena in the BCS-BEC crossover regime of a superfluid Fermi gas.},

  doi          = {10.1103/PHYSREVA.82.043630},

  url          = {https://www.osti.gov/biblio/21454817},
  journal      = {Physical Review. A},

  issn         = {1050-2947},

  number       = 4,

  volume       = 82,

  place        = {United States},

  year         = {2010},

  month        = {10}

}

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