Magnetic fusion devices operate at regimes characterized by extremely high temperatures and low densities, for which the charged particles motion is well described by classical mechanics. This is not true, however, for solid-state metallic objects: their density approaches 1028 m−3, so that the average interparticle distance is shorter than the de Broglie wavelength, which characterizes the spread of the electron wave function. Under these conditions, the conduction electrons behave as a true quantum plasma even at room temperature. Here, we shall illustrate the impact of quantum phenomena on the electron dynamics in metallic objects of nanometric size, particularly thin metallic films excited by short laser pulses. Further, we will discuss more recent results on regimes that involve spin and relativistic effects.