Normal-state properties of spin-orbit-coupled Fermi gases in the upper branch of the energy spectrum

We investigate normal-state properties of spin-orbit-coupled Fermi gases with repulsive s-wave interaction, in the absence of molecule formation, i.e., in the so-called upper branch. Within the framework of random-phase approximation, we derive analytical expressions for the quasiparticle lifetime tau(s), the effective mass m*(s), and the Green's function renormalization factor Z(s) in the presence of Rashba spin-orbit coupling. In contrast to spin-orbit-coupled electron gas with Coulomb interaction, we show that the modifications are dependent on the Rashba band index s and occur in the first order of the spin-orbit-coupling strength. We also calculate experimental observables such as spectral weight, density of state, and specific heat, which exhibit significant differences from their counterparts without spin-orbit coupling. We expect our microscopic calculations of these Fermi-liquid parameters would have immediate applications to the spin-orbit-coupled Fermi gases in the upper branch of the energy spectrum.