Finite-temperature phase diagram of a two-component Fermi gas with density imbalance
Finite-temperature phase diagram of a two-component Fermi gas with density imbalance
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DOI：
10.1103/physrevb.74.214516
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发表时间：
2006-12-01
影响因子：
3.7
通讯作者：
Zhuang, Pengfei
中科院分区：
文献类型：
--
作者：
He, Lianyi;Jin, Meng;Zhuang, Pengfei
研究了有限温度下密度不平衡的双组分费米气体中可能存在的超流相。在一般的四费米子相互作用理论框架下，在BCS区求解了固定数密度约束下的对能隙和对动量的能隙差距方程，并通过计算超流密度和数密度系数分析了不同相态的稳定性.均匀超流只在高温和低的非对称性下才稳定，非均匀Larkin-Ovchinnikov-Fudde-Ferrell态在低温和高的非对称性下才稳定，在它们之间还存在着另一种可能的非均匀相，即相分离。用解析和数值方法计算了超流相和正常相的临界温度和相变级数。对于化学势固定的体系，我们在温度和数不对称平面上得到的相图与在温度和化学势差平面上得到的相图有很大的不同。
We investigated possible superfluid phases at finite temperature in a two-component Fermi gas with density imbalance. In the frame of a general four-fermion interaction theory, we solved in the BCS region the gap equations for the pairing gap and pairing momentum under the restriction of fixed number densities and analyzed the stability of different phases by calculating the superfluid density and number susceptibilities. The homogeneous superfluid is stable only at high temperature and low number asymmetry, the inhomogeneous Larkin-Ovchinnikov-Fudde-Ferrell state survives at low temperature and high number asymmetry, and in between them there exists another possible inhomogeneous phase, that of phase separation. The critical temperatures and the orders of the phase transitions among the superfluid phases and normal phase are calculated analytically and numerically. The phase diagram we obtained in the temperature and number asymmetry plane is quite different from the one in the temperature and chemical potential difference plane for a system with fixed chemical potentials.