Theory of quasi-one-dimensional imbalanced Fermi gases
Theory of quasi-one-dimensional imbalanced Fermi gases
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DOI：
10.1103/physreva.78.063605
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发表时间：
2008-04
影响因子：
2.9
通讯作者：
E. Zhao;W. Liu
中科院分区：
文献类型：
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作者：
E. Zhao;W. Liu
我们提出了一种具有自旋不平衡的弱耦合一维超冷吸引费米气体（一维管）晶格阵列的理论，其中强烈的管内量子涨落使平均场理论无效。我们首先基于一维单管问题的 Bethe ansatz 解构建了一个有效的场论，该场论精确地处理自旋电荷混合。我们证明一维 Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) 态是一种双组分 Luttinger 液体，其基本激发是同时带有电荷和自旋的分数态。我们通过重正化群分析分析了 1D FFLO 状态对管间隧道效应的不稳定性，发现它会流入极化费米液体或 FFLO 超流体，具体取决于相互作用强度和自旋不平衡的大小。我们获得了准一维系统的相图，并进一步确定了管间耦合的超流体转变温度的比例。
We present a theory for a lattice array of weakly coupled one-dimensional ultracold attractive Fermi gases (1D tubes) with spin imbalance, where strong intratube quantum fluctuations invalidate mean-field theory. We first construct an effective field theory, which treats spin-charge mixing exactly, based on the Bethe ansatz solution of the 1D single tube problem. We show that the 1D Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state is a two-component Luttinger liquid, and its elementary excitations are fractional states carrying both charge and spin. We analyze the instability of the 1D FFLO state against intertube tunneling by renormalization group analysis, and find that it flows into either a polarized Fermi liquid or a FFLO superfluid, depending on the magnitude of interaction strength and spin imbalance. We obtain the phase diagram of the quasi-1D system and further determine the scaling of the superfluid transition temperature with intertube coupling.