Abstract
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.
| Original language | English |
|---|---|
| Article number | 013618 |
| Journal | Physical Review A - Atomic, Molecular, and Optical Physics |
| Volume | 89 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2014 Jan 22 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Pseudogap phenomenon and effects of population imbalance in the normal state of a unitary Fermi gas. / Kashimura, Takashi; Watanabe, Ryota; Ohashi, Yoji.
In: Physical Review A - Atomic, Molecular, and Optical Physics, Vol. 89, No. 1, 013618, 22.01.2014.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pseudogap phenomenon and effects of population imbalance in the normal state of a unitary Fermi gas
AU - Kashimura, Takashi
AU - Watanabe, Ryota
AU - Ohashi, Yoji
PY - 2014/1/22
Y1 - 2014/1/22
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84894474130&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84894474130&partnerID=8YFLogxK
U2 - 10.1103/PhysRevA.89.013618
DO - 10.1103/PhysRevA.89.013618
M3 - Article
AN - SCOPUS:84894474130
VL - 89
JO - Physical Review A
JF - Physical Review A
SN - 2469-9926
IS - 1
M1 - 013618
ER -