Isolated rings of mesoscopic dimensions. Quantum coherence and persistent currents

Persistent currents in small nonsuperconducting rings threaded by a magnetic flux are a manifestation of novel quantum effects in submicron systems. We present theoretical results for one-channel and multichannel systems concerning the dependence of the current amplitude on the number of channels and geometry, temperature, and degree of disorder. Inelastic scattering is considered for one-channel loops only. We also discuss the observability of the effect.