Nonperturbative approach to quench dynamics. I. Exact time evolution and steady state of the nonequilibrium Kondo model Article Swipe
We present a nonperturbative method for calculating the time-dependent many body wavefunction that follows a local quench, and we use it to find the exact time evolution of the nonequilibrium Kondo model driven by a bias voltage. The method also works in other quantum impurity models and may be of even wider applicability; integrability does not appear to play any role. In the case of the Kondo model, we show that the long time limit (with the system size taken to infinity first) of the time-evolving wavefunction is a current-carrying nonequilibrium steady state. We find a series expression for the average electric current, which we use in the next paper to identify a new universal regime of strong ferromagnetic coupling with Kondo temperature $T_K = D e^{\frac{3\pi^2}{8} \rho J}$.
