Trapped polarized Fermi gas at unitarity

We consider population-imbalanced two-component Fermi gases under external harmonic confinement interacting through short-range two-body potentials with diverging s-wave scattering length. Using the fixed-node diffusion Monte Carlo method, the energies of the "normal state" are determined as functions of the population-imbalance and the number of particles. The energies of the trapped system follow, to a good approximation, a universal curve even for fairly small systems. A simple parameterization of the universal curve is presented and related to the equation of state of the bulk system.

我们考虑处于外谐波约束下的粒子数不平衡的双组分费米气体，它们通过具有发散的s波散射长度的短程两体势相互作用。利用固定节点扩散蒙特卡罗方法，确定了“正常态”的能量作为粒子数不平衡和粒子数的函数。即使对于相当小的系统，被束缚系统的能量也能很好地近似遵循一条普适曲线。给出了普适曲线的一种简单参数化形式，并将其与体系统的物态方程相关联。