Abstract:
A transient process starting at a finite initial time is considered as a restart process embedded in a host process, which serves to prepare the (non-equilibrium) initial state. The Non-equilibrium Green's Function for the restart process involves in general the so-called correlated initial conditions appearing as singular terms in the transient self-energy. The full self-energy can be expressed in terms of the host process GF and self-energies by means of time partitioning, a novel general technique for treating problems, in which past and future are separated by a privileged time instant.