Abstract
We theoretically investigate magnetic properties of a trapped ultracold Fermi gas. Including pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a harmonic trap in the local density approximation, we calculate the local spin susceptibility χt(r,T) in the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover region. We show that pairing fluctuations cause nonmonotonic temperature dependence of χt(r,T). Although this behavior looks similar to the spin-gap phenomenon associated with pairing fluctuations in a uniform Fermi gas, the trapped case is found to also be influenced by the temperature-dependent density profile, in addition to pairing fluctuations. We demonstrate how to remove this extrinsic effect from χt(r,T), to study the interesting spin-gap phenomenon purely originating from pairing fluctuations. Since experiments in cold-atom physics are always done in a trap, our results would be useful for the assessment of preformed pair scenario, from the viewpoint of spin-gap phenomenon.
| Original language | English |
|---|---|
| Article number | 033614 |
| Journal | Physical Review A |
| Volume | 96 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2017 Sep 11 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Spin susceptibility and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas. / Tajima, Hiroyuki; Hanai, Ryo; Ohashi, Yoji.
In: Physical Review A, Vol. 96, No. 3, 033614, 11.09.2017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Spin susceptibility and effects of a harmonic trap in the BCS-BEC crossover regime of an ultracold Fermi gas
AU - Tajima, Hiroyuki
AU - Hanai, Ryo
AU - Ohashi, Yoji
PY - 2017/9/11
Y1 - 2017/9/11
N2 - We theoretically investigate magnetic properties of a trapped ultracold Fermi gas. Including pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a harmonic trap in the local density approximation, we calculate the local spin susceptibility χt(r,T) in the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover region. We show that pairing fluctuations cause nonmonotonic temperature dependence of χt(r,T). Although this behavior looks similar to the spin-gap phenomenon associated with pairing fluctuations in a uniform Fermi gas, the trapped case is found to also be influenced by the temperature-dependent density profile, in addition to pairing fluctuations. We demonstrate how to remove this extrinsic effect from χt(r,T), to study the interesting spin-gap phenomenon purely originating from pairing fluctuations. Since experiments in cold-atom physics are always done in a trap, our results would be useful for the assessment of preformed pair scenario, from the viewpoint of spin-gap phenomenon.
AB - We theoretically investigate magnetic properties of a trapped ultracold Fermi gas. Including pairing fluctuations within the framework of an extended T-matrix approximation, as well as effects of a harmonic trap in the local density approximation, we calculate the local spin susceptibility χt(r,T) in the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover region. We show that pairing fluctuations cause nonmonotonic temperature dependence of χt(r,T). Although this behavior looks similar to the spin-gap phenomenon associated with pairing fluctuations in a uniform Fermi gas, the trapped case is found to also be influenced by the temperature-dependent density profile, in addition to pairing fluctuations. We demonstrate how to remove this extrinsic effect from χt(r,T), to study the interesting spin-gap phenomenon purely originating from pairing fluctuations. Since experiments in cold-atom physics are always done in a trap, our results would be useful for the assessment of preformed pair scenario, from the viewpoint of spin-gap phenomenon.
UR - http://www.scopus.com/inward/record.url?scp=85029575263&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85029575263&partnerID=8YFLogxK
U2 - 10.1103/PhysRevA.96.033614
DO - 10.1103/PhysRevA.96.033614
M3 - Article
AN - SCOPUS:85029575263
VL - 96
JO - Physical Review A
JF - Physical Review A
SN - 2469-9926
IS - 3
M1 - 033614
ER -