Pseudogap in fermionic density of states in the BCS-BEC crossover of atomic Fermi gases

Abstract

We study pseudogap behaviors of ultracold Fermi gases in the BCS-BEC crossover region. We calculate the density of states (DOS), as well as the single-particle spectral weight, above the superfluid transition temperature $T_{\mathrm{c}}$ including pairing fluctuations within a $T$-matrix approximation. We find that DOS exhibits a pseudogap structure in the BCS-BEC crossover region, which is most remarkable near the unitarity limit. We determine the pseudogap temperature $T^{\ast }$ at which the pseudogap structure in DOS disappears. We also introduce another temperature $T^{\ast \ast }$ at which the BCS-like double-peak structure disappears in the spectral weight. While one finds $T^{\ast }>T^{\ast \ast }$ in the BCS regime, $T^{\ast \ast }$ becomes higher than $T^{\ast }$ in the crossover and BEC regime. We also determine the pseudogap region in the phase diagram in terms of temperature and pairing interaction.

6 pages, 4 figures, Proceedings of QFS 2009

References in corpus (5)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Scanning tunneling spectroscopy of high-temperature superconductors
• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas

Cited by in corpus (2)

• Pseudogaps in strongly interacting Fermi gases
• Evolution of the Pseudogap in a polarized Fermi gas