Universal equation of state and pseudogap in the two-dimensional Fermi gas.
Universal equation of state and pseudogap in the two-dimensional Fermi gas.
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DOI：
10.1103/physrevlett.112.135302
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发表时间：
2013-11
影响因子：
8.6
通讯作者：
M. Bauer;M. Parish;T. Enss
中科院分区：
文献类型：
--
作者：
M. Bauer;M. Parish;T. Enss
我们确定了一个均匀的二维费米气体在正常状态下使用的Luttinger-Ward，或自洽的T-矩阵，方法的热力学性质和光谱函数。密度状态方程偏离强烈的理想费米气体，即使是中等的相互作用，我们的计算表明，温度有一个明显的影响，从弱到强耦合的交叉中的压力，与最近的实验一致。我们还计算了一个有限系统在交叉区域的超流转变温度。有一个明显的赝能隙制度以上的转变温度：光谱函数显示Bogoliubov类色散与回弯，和状态的密度显着抑制附近的化学势。在低温下的接触密度增加与相互作用，并比较以及与实验和零温度蒙特卡罗结果。
We determine the thermodynamic properties and the spectral function for a homogeneous two-dimensional Fermi gas in the normal state using the Luttinger-Ward, or self-consistent T-matrix, approach. The density equation of state deviates strongly from that of the ideal Fermi gas even for moderate interactions, and our calculations suggest that temperature has a pronounced effect on the pressure in the crossover from weak to strong coupling, consistent with recent experiments. We also compute the superfluid transition temperature for a finite system in the crossover region. There is a pronounced pseudogap regime above the transition temperature: the spectral function shows a Bogoliubov-like dispersion with backbending, and the density of states is significantly suppressed near the chemical potential. The contact density at low temperatures increases with interaction and compares well with both experiment and zero-temperature Monte Carlo results.