Relationship between the noise-induced persistent current and the dephasing rate
ac noise in disordered conductors causes both dephasing of the electron wave functions and a dc current around a mesoscopic ring. We demonstrate that the dephasing rate tau(-1)(varphi) in long wires and the dc current <I>, induced by the same noise and averaged over an ensemble of small rings, are connected in a remarkably simple way: <I>tau(varphi) = C(beta)e. Here e is an electron charge, and the constant C(beta) approximately 1 depends on the Dyson symmetry class. The relationship seems to agree reasonably with experiments. This suggests that the two puzzles, anomalously large persistent current and the low-temperature saturation of the dephasing, may have a common solution.
Kravtsov
VE
The Abdus Salam International Centre for Theoretical Physics, P.O.B. 586, 34100 Trieste, Italy and Landau Institute for Theoretical Physics, 2 Kosygina Street, 117940 Moscow, Russia and and Centre for Advanced Study, Drammensveien 78, N-0271 Oslo,
Altshuler
BL