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arXiv 0711.4065cond-mat.supr-concond-mat.str-el
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结合非均匀背景势的一维、二维和三维光晶格中的FFLO态

FFLO state in 1, 2, and 3 dimensional optical lattices combined with a non-uniform background potential

T. K. Koponen, T. Paananen, J. -P. Martikainen, M. R. Bakhtiari, P. Torma

摘要:

本文研究了1-3维光晶格中非平衡双组分费米气体在有限温度和零温度下的相图,考虑了FFLO、Sarma/breaked对、BCS和正常态以及相分离的可能性。特别是,相对于平均化学势和化学电势差的两个组件的相图被认为是,因为这给出了必要的信息,将发生在存在一个额外的(谐波)限制的阶段的壳结构。这些1、2和3维的相图以惊人的方式显示了范霍夫奇点对FFLO状态的影响。虽然我们专注于人口不平衡的气体,结果也是相关的(有效)质量不平衡的情况下。我们证明了LDA计算,各种壳结构,如正常的FFLO-BCS-FFLO-正常的,或FFLO-正常的,是可能存在的背景谐波陷阱。相位反映在噪声相关中:特别是在1D中,未配对的原子在费米海中留下了清晰的FFLO状态的签名,作为零相关区域(“突破”)。这种强烈的签名既发生在1D晶格上,也发生在1D连续体上。我们还讨论了Hartree能量和Gorkov修正对相图的影响。

英文摘要:

We study the phase diagram of an imbalanced two-component Fermi gas in optical lattices of 1-3 dimensions, considering the possibilities of the FFLO, Sarma/breached pair, BCS and normal states as well as phase separation, at finite and zero temperatures. In particular, phase diagrams with respect to average chemical potential and the chemical potential difference of the two components are considered, because this gives the essential information about the shell structures of phases that will occur in presence of an additional (harmonic) confinement. These phase diagrams in 1, 2 and 3 dimensions show in a striking way the effect of Van Hove singularities on the FFLO state. Although we focus on population imbalanced gases, the results are relevant also for the (effective) mass imbalanced case. We demonstrate by LDA calculations that various shell structures such as normal-FFLO-BCS-FFLO-normal, or FFLO-normal, are possible in presence of a background harmonic trap. The phases are reflected in noise correlations: especially in 1D the unpaired atoms leave a clear signature of the FFLO state as a zero-correlation area (``breach'') within the Fermi sea. This strong signature occurs both for a 1D lattice as well as for a 1D continuum. We also discuss the effect of Hartree energies and the Gorkov correction on the phase diagrams.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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