Non-Gaussian variational approach to Fermi polarons in one- and two-dimensional lattices

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 via the Lee-Low-Pines transformation. The ground state with a fixed total momentum can be obtained via imaginary-time evolution. For the...