Spin polarized nonrelativistic fermions in 1+1 dimensions

Abstract

We study by Monte Carlo methods the thermodynamics of a spin polarized gas of nonrelativistic fermions in 1+1 dimensions. The main result of this work is that our action suffers no significant sign problem for any spin polarization in the region relevant for dilute degenerate Fermi gases. This lack of sign problem allows us to study attractive spin polarized fermions nonperturbatively at spin polarizations not previously explored. For some parameters values we verify results previously obtained by methods which include an uncontrolled step like complex Langevin and/or analytical continuation from imaginary chemical potential. For others, larger values of the polarization, we deviate from these previous results.