Pair correlations of an expanding superfluid Fermi gas.
Pair correlations of an expanding superfluid Fermi gas.
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DOI：
10.1103/physrevlett.97.100405
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发表时间：
2006-04
影响因子：
8.6
通讯作者：
C. Lobo;I. Carusotto;S. Giorgini;A. Recati;S. Stringari
中科院分区：
文献类型：
--
作者：
C. Lobo;I. Carusotto;S. Giorgini;A. Recati;S. Stringari
研究了膨胀气体的对相关函数，重点研究了超流体费米气体在零温度下的bc - bcs交叉。在唯一性量子蒙特卡罗模拟显示，由于自旋上下通道中的相互作用，在短距离内出现了相当大的聚束效应，比汉伯里-布朗-特维斯效应中热玻色子所表现出的更大。我们提出了对相关函数的局部平衡分析，我们预测即使捕获势是各向异性的，在膨胀过程中对相关函数将保持各向同性，与密度的行为相反。对相关函数的各向同性是一个实验上可获得的特征，它与非相互作用气体的情况有明显的区别，可以理解为违反标度的结果。
The pair correlation function of an expanding gas is investigated with an emphasis on the BEC-BCS crossover of a superfluid Fermi gas at zero temperature. At unitarity quantum Monte Carlo simulations reveal the occurrence of a sizable bunching effect due to interactions in the spin up-down channel which, at short distances, is larger than that exhibited by thermal bosons in the Hanbury-Brown-Twiss effect. We propose a local equilibrium ansatz for the pair correlation function which we predict will remain isotropic during the expansion even if the trapping potential is anisotropic, in contrast with the behavior of the density. The isotropy of the pair correlation function is an experimentally accessible signature, which makes a clear distinction with respect to the case of noninteracting gases and can be understood as a consequence of the violation of scaling.