Pseudogap phenomenon and effects of population imbalance in the normal state of a unitary Fermi gas

Takashi Kashimura, Ryota Watanabe, Yoji Ohashi

研究成果: Article査読

13 被引用数 (Scopus)


We investigate strong-coupling corrections to single-particle excitations in the normal state of a spin-polarized unitary Fermi gas. Within the framework of an extended T-matrix approximation, we calculate the single-particle density of states, as well as the single-particle spectral weight, to show that the so-called pseudogap phenomenon gradually disappears with increasing magnitude of an effective magnetic field. In the highly spin-polarized regime, the calculated spin polarization as a function of the effective magnetic field agrees well with the recent experiment on a 6Li Fermi gas. Although this experiment has been considered to be incompatible with the existence of the pseudogap in an unpolarized Fermi gas, our result clarifies that the observed spin polarization in the highly spin-polarized regime and the pseudogap in the unpolarized limit can be explained in a consistent manner when one correctly includes effects of population imbalance on single-particle excitations. Since it is a crucial issue to clarify whether the pseudogap exists or not in the BCS-BEC crossover regime of an ultracold Fermi gas, our results would be useful for the understanding of this strongly interacting fermion system.

ジャーナルPhysical Review A - Atomic, Molecular, and Optical Physics
出版ステータスPublished - 2014 1月 22

ASJC Scopus subject areas

  • 原子分子物理学および光学


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