论文标题
一种和二维晶格中费米极性的非高斯变异方法
A Non-Gaussian Variational Approach to Fermi Polarons in One- and Two-dimensional Lattices
论文作者
论文摘要
我们研究了一个流动旋转杂质的费米极化问题，这些杂质在浴缸上浸入了由一维正方形晶格中的旋转费米子组成的浴室。我们通过通过Lee-Low-Pines转换分离杂质和背景后，通过非高斯状态应用变异方法来解决这个问题。固定总动量的基态可以通过假想时间的演变获得变异参数。对于一维情况，将变异结果与具有良好一致的矩阵乘积方法的数值解相提并论。在二维晶格中，我们专注于稀释极限，并找到一个偏振子 - 分子的演化，与以前通过变异和量子蒙特卡洛方法获得的结果一致。与以前的作品相比，我们的方法在考虑的整个参数区域中提供了最低的基态能量，并且具有明显的优势，因为它不需要以先验性}的形式假设{\ it}变异波函数的任何特定形式。
We study the Fermi polaron problem of one mobile spin-up impurity immersed atop the bath consisting of spin-down fermions in one- and two-dimensional square lattices. We solve this problem by applying a variational approach with non-Gaussian states after separating the impurity and the background by the Lee-Low-Pines transformation. The ground state for a fixed total momentum can be obtained via imaginary time evolution for the variational parameters. For the one-dimensional case, the variational results are compared with numerical solutions of the matrix product state method with excellent agreement. In two-dimensional lattices, we focus on the dilute limit, and find a polaron--molecule evolution in consistence with previous results obtained by variational and quantum Monte Carlo methods for models in continuum space. Comparing to previous works, our method provides the lowest ground state energy in the entire parameter region considered, and has an apparent advantage as it does not need to assume {\it in priori} any specific form of the variational wave function.
