  We discuss the transient effects in the Anderson impurity model that occur
when two fermionic continua with finite bandwidths are instantaneously coupled
to a central level. We present results for the analytically solvable
noninteracting resonant level system first and then consistently extend them to
the interacting case using the conventional perturbation theory and recently
developed nonequilibrium Monte Carlo simulation schemes. The main goal is to
gain an understanding of the full time-dependent nonlinear current-voltage
characteristics and the population probability of the central level. We find
that, contrary to the steady state, the transient dynamics of the system
depends sensitively on the bandwidth of the electrode material.
