Third order corrections to the ground state energy of the polarized diluted gas of spin $1/2$ fermions

Abstract

We present the results of the computation of the third order corrections to the ground state energy of the diluted polarized gas of nonrelativistic spin $1/2$ fermions interacting through a spin-independent repulsive two-body potential. The corrections are computed within the effective field theory approach which does not require specifying the interaction potential explicitly but only to characterize it by only a few parameters - the scattering lengths $a_0$, $a_1,\dots$ and effective radii $r_0,\dots$ - measurable in low energy fermion-fermion elastic scattering. The corrections are computed semi-analytically, that is are expressed in terms of two functions of the system's polarization. The functions are given by the integrals which can be easily evaluated using the Mathematica built-in routines for numerical integration.