Non-equilibrium steady states in quenched s-wave superfluids

Nature and microscopic structure of the non-equilibrium many-body states in strongly interacting quantum systems remains one of most active research areas in physics. In this work, we study the steady states, which appear in a s-wave superfluid at zero temperature following a quench of the pairing strength. We use the BCS Hamiltonian which we solve exactly in the thermodynamic limit using classical integrability. We obtain a generic phase diagram of the resulting steady states for quenches corresponding to an arbitrary change of the pairing strength. We calculate single particle distribution function for each of the steady states that we find. In addition, we determine the asymptotic behavior of the pairing amplitude at long times. The experimental signatures of the steady states will also be discussed.