  In this paper, the exact transient quantum transport of non-interacting
nanostructures is investigated in the presence of initial system-lead
correlations and initial lead-lead correlations for a device system coupled to
general electronic leads. The exact master equation incorporating with initial
correlations is derived through the extended quantum Langevin equation. The
effects of the initial correlations are manifested through the time-dependent
fluctuations contained explicitly in the exact master equation. The transient
transport current incorporating with initial correlations is obtained from the
exact master equation. The resulting transient transport current can be
expressed in terms of the single-particle propagating and correlation Green
functions of the device system. We show that the initial correlations can
affect quantum transport not only in the transient regime, but also in the
steady-state limit when system-lead couplings are strong enough so that
electron localized bound states occur in the device system.
