Rosenberg Peter, Chiesa Simone, Zhang Shiwei
Department of Physics, College of William and Mary, Williamsburg, VA 23188, USA.
J Phys Condens Matter. 2015 Jun 10;27(22):225601. doi: 10.1088/0953-8984/27/22/225601. Epub 2015 May 18.
We investigate different ground-state phases of attractive spin-imbalanced populations of fermions in three-dimensional optical lattices. Detailed numerical calculations are performed using Hartree-Fock-Bogoliubov theory to determine the ground-state properties systematically for different values of density, spin polarization and interaction strength. We first consider the high density and low polarization regime, in which the effect of the optical lattice is most evident. We then proceed to the low density and high polarization regime where the effects of the underlying lattice are less significant and the system begins to resemble a continuum Fermi gas. We explore the effects of density, polarization and interaction on the character of the phases in each regime and highlight the qualitative differences between the two regimes. In the high-density regime, the order is found to be of Larkin-Ovchinnikov type, linearly oriented with one characteristic wave vector but varying in its direction with the parameters. At lower densities the order parameter develops more structures involving multiple wave vectors.
我们研究了三维光学晶格中吸引性自旋不平衡费米子体系的不同基态相。利用哈特里 - 福克 - 博戈留波夫理论进行了详细的数值计算，以便系统地确定不同密度、自旋极化和相互作用强度值下的基态性质。我们首先考虑高密度和低极化区域，其中光学晶格的效应最为明显。然后我们进入低密度和高极化区域，此时底层晶格的效应不太显著，系统开始类似于连续费米气体。我们探讨了密度、极化和相互作用对每个区域中相的特征的影响，并突出了两个区域之间的定性差异。在高密度区域，发现序是拉金 - 奥夫钦尼科夫型的，沿一个特征波矢线性取向，但方向随参数变化。在较低密度下，序参量会发展出更多涉及多个波矢的结构。
