In correlated electron systems, in particular
in reduced dimensions, quantum fluctuations of charge and spin induce unusual
behaviour. We present two examples: a
two-dimensional electron system in a incoherent metal phase and a
zero-dimensional system in the presence of a stationary current. In the first case the Dynamical Mean Field
Theory is used to calculate the single particle and spin excitation
spectra. A pseudogap is found for the
weakly hole-doped half-filled system, as a consequence of strong quantum
fluctuations. In the second case
electron transport through a quantum dot in the Kondo regime is discussed. It is shown that the decoherence induced by
a finite current suppresses the Kondo effect.