Physical properties of single-electron devices in the weak Coulomb blockade regime are significantly dependent on non-perturbative effects. They arise as instanton solutions of equations of motion for the corresponding Ambegaokar-Eckern-Schön action. In equilibrium those solutions are known as Korshunov instantons. In this paper we study non-equilibrium Ambegaokar-Eckern-Schön action using Keldysh technique. We found instantons for the most general stationary out-of-equilibrium state. We also found that action saddle-point value assumes a universal value irrespective of the stationary non-equilibrium state.
|Journal||Physics Letters, Section A: General, Atomic and Solid State Physics|
|Publication status||Published - 17 Dec 2021|