NORMAL PERSISTENT CURRENTS

This article reviews recent advances in mesoscopic physics, namely exp erimental and theoretical investigations of persistent (equilibrium) c urrents in normal metal rings. While theory and experiment are consist ent in the ballistic regime, theoretical studies so far have not been able to account for the unexpectedly huge currents observed experiment ally in disordered (diffusive) samples, in which the elastic mean free path is much less than the circumference of the rings.