Real-time spin-charge separation in one-dimensional Fermi gases from generalized hydrodynamics

We revisit early suggestions to observe spin-charge separation (SCS) in cold-atom settings in the time domain by studying one-dimensional repulsive Fermi gases in a harmonic potential, where pulse perturbations are initially created at the center of the trap. We analyze the subsequent evolution using generalized hydrodynamics (GHD), which provide an exact description, at large space-time scales, for arbitrary temperature T, particle density, and interactions. At T = 0 and vanishing magnetic field, we find that, after a nontrivial transient regime, spin and charge dynamically decouple up to perturbatively small corrections which we quantify. In this limit, our results can be understood based on a simple phase-space hydrodynamic picture. At finite temperature, we solve numerically the GHD equations, showing that for low T > 0 effects of SCS survive and characterize explicitly the value of T for which the two distinguishable excitations melt.

Automated summary

This study revisits early suggestions to observe spin-charge separation in cold-atom settings by studying the evolution of one-dimensional repulsive Fermi gases in a harmonic potential. The results show that at low temperature and zero magnetic field, spin and charge dynamically decouple with quantitatively small quantum corrections. At finite temperature, the effects of spin-charge separation still persist, and the specific temperature at which the two distinguishable excitations melt is explicitly characterized through numerical simulations of the GHD equations.