Spectral Properties of One-Dimensional Fermi Systems after an Interaction Quench

Abstract

We show that the single-particle spectral properties of gapless one-dimensional Fermi systems in the Luttinger liquid state reached at intermediate times after an abrupt quench of the two-particle interaction are highly indicative of the unusual nonequilibrium nature of this state. The line shapes of the momentum-integrated and -resolved spectral functions strongly differ from their ground state as well as finite temperature equilibrium counterparts. Using an energy resolution improved version of radio-frequency spectroscopy of quasi-one-dimensional cold Fermi gases, it should be possible to experimentally identify this nonequilibrium state by its pronounced spectral signatures.