Pseudogap temperature and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas

Shunji Tsuchiya, Ryota Watanabe, Yoji Ohashi

研究成果: Article査読

34 被引用数 (Scopus)

抄録

We theoretically investigate excitation properties in the pseudogap regime of a trapped Fermi gas. Using a combined T-matrix theory with the local density approximation, we calculate strong-coupling corrections to single-particle local density of states (LDOS), as well as the single-particle local spectral weight (LSW). Starting from the superfluid phase transition temperature Tc, we clarify how the pseudogap structures in these quantities disappear with increasing the temperature. As in the case of a uniform Fermi gas, LDOS and LSW give different pseudogap temperatures T* and T ** at which the pseudogap structures in these quantities completely disappear. Determining T* and T ** over the entire BCS (Bardeen-Cooper- Schrieffer)-BEC (Bose-Einstein condensation) crossover region, we identify the pseudogap regime in the phase diagram with respect to the temperature and the interaction strength. We also show that the so-called back-bending peak recently observed in the photoemission spectra by the JILA group may be explained as an effect of pseudogap phenomenon in the trap center. Since strong pairing fluctuations, spatial inhomogeneity, and finite temperatures are important keys in considering real cold Fermi gases, our results would be useful for clarifying normal-state properties of this strongly interacting Fermi system.

本文言語English
論文番号043647
ジャーナルPhysical Review A - Atomic, Molecular, and Optical Physics
84
4
DOI
出版ステータスPublished - 2011 10月 31

ASJC Scopus subject areas

  • 原子分子物理学および光学

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