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摘要翻译：
我们系统地研究了一维自旋极化费米气体中的量子相。用三种比较的理论方法研究了零温相图：单平面波形式的序参量的平均场理论，用Bogoliubov-de Gennes方程自洽确定序参量的平均场理论，以及精确可解的Bethe ansatz方法。我们发现，处于完全配对BCS态和完全极化正态之间的空间非均匀Fulde-Ferrell-Larkin-Ovchinnikov相占据了均匀气体相图的大部分。从BCS态到Fulde-Ferrell-Larkin-Ovchinnikov相的相变是二级相变，因此在一维均匀极化气体中不存在相分离态。这与三维情况形成鲜明对比，在三维情况下，相分离区被预测在相图中占据非常大的空间。我们推测三维相分离相优势的预测可能是非自洽平均场近似的伪影，该近似在三维极化费米气体的研究中得到了广泛的应用。我们还考虑了谐波囚禁势对相图的影响，发现在这种情况下，囚禁通常导致相分离，这与三维囚禁气体的实验观察相一致。最后，我们研究了Fulde-Ferrell-Larkin-Ovchinnikov Ansatz体系的局域费米子态密度。发现了一个双能隙结构，可以作为Fulde-Ferrell-Larkin-Ovchinnikov态的实验探针。
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英文标题：
《Fulde-Ferrell-Larkin-Ovchinnikov states in one-dimensional
spin-polarized ultracold atomic Fermi gases》
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作者：
Xia-Ji Liu, Hui Hu, and Peter D. Drummond
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最新提交年份：
2007
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分类信息：
一级分类：Physics 物理学
二级分类：Statistical Mechanics 统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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一级分类：Physics 物理学
二级分类：Strongly Correlated Electrons 强关联电子
分类描述：Quantum magnetism, non-Fermi liquids, spin liquids, quantum criticality, charge density waves, metal-insulator transitions
量子磁学，非费米液体，自旋液体，量子临界性，电荷密度波，金属-绝缘体跃迁
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英文摘要：
We present a systematic study of quantum phases in a one-dimensional spin-polarized Fermi gas. Three comparative theoretical methods are used to explore the phase diagram at zero temperature: the mean-field theory with either an order parameter in a single-plane-wave form or a self-consistently determined order parameter using the Bogoliubov-de Gennes equations, as well as the exact soluble Bethe ansatz method. We find that a spatially inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov phase, which lies between the fully paired BCS state and the fully polarized normal state, dominates most of the phase diagram of a uniform gas. The phase transition from the BCS state to the Fulde-Ferrell-Larkin-Ovchinnikov phase is of second order, and therefore there are no phase separation states in one-dimensional homogeneous polarized gases. This is in sharp contrast to the three-dimensional situation, where a phase separation regime is predicted to occupy a very large space in the phase diagram. We conjecture that the prediction of the dominance of the phase separation phases in three dimension could be an artifact of the non-self-consistent mean-field approximation, which is heavily used in the study of three-dimensional polarized Fermi gases. We consider also the effect of a harmonic trapping potential on the phase diagram, and find that in this case the trap generally leads to phase separation, in accord with the experimental observations for a trapped gas in three dimension. We finally investigate the local fermionic density of states of the Fulde-Ferrell-Larkin-Ovchinnikov ansatz. A two-energy-gap structure is shown up, which could be used as an experimental probe of the Fulde-Ferrell-Larkin-Ovchinnikov states.
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PDF链接：
https://arxiv.org/pdf/707.4066
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