We demonstrate that persistent current in meso- and nanorings may fluctuate
down to zero temperature provided the current operator does not commute with
the total Hamiltonian of the system. For a model of a quantum particle on a
ring we explicitly evaluate PC noise power which has a form of sharp peaks
which become broadened for multi-channel rings or in the presence of
dissipation. PC noise can be tuned by an external magnetic flux which is a
fundamental manifestation of quantum coherence in the system.Comment: 4 pages, 1 figur

Andrei D Zaikin

Andrew G Semenov

Golubev D S