Exact Quench Dynamics of Open System Kondo Model

Motivated by recent cold atom experiments, we consider the quench dynamics in the Kondo system consisting of a Fermi sea (the lead) coupled via spin exchange to spin-1/2 impurity. Starting from an initial state where the lead and the impurity are decoupled, we calculate the time evolution of the system after the coupling is turned on. As an observable we compute the expectation value of impurity spin as a function of time. Moreover, we will discuss the ongoing efforts on computing the Loschmidt echo.