2010/07/22 by Ryota Watanabe, Shunji Tsuchiya, Yoji Ohashi · 1 citation
Physics and Astronomy · #Atomic and Subatomic Physics Research #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Cuprate #Electron #Fermi gas #Pairing #Physics #Physics of Superconductivity and Magnetism #Pseudogap #Quantum mechanics #Superconductivity #Superfluidity #cond-mat.quant-gas
paper · pdf · doi:10.1103/physreva.82.043630
published as Phys. Rev. A 82, 043630 (2010) · 22 pages, 8 figures
arxiv created 2010/07/22 · openalex publication_date 2010/10/28 · arxiv updated 2015/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 Tc. We clarify how the pseudogap in the normal state evolves into the superfluid gap, as one passes through Tc. 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 Tc. 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.