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

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:
 [1];  [2];  [1]
  1. Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)
  2. Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)
Publication Date:
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.
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
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.
@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}
}