1994/05/23 by B. L. Altshuler, L. S. Levitov, A. Yu. Yakovets
Physics and Astronomy · #cond-mat
published as JETP Lett. 59, 857 (1994) · 6 pages, figures by request, RevTeX, Landau Institute preprint 261/6437
arxiv created 1994/05/23 · arxiv updated 2009/11/30
Current fluctuations are studied in a mesoscopic conductor using non-equilibrium Keldysh technique. We derive a general expression for the fluctuations in the presence of a time dependent voltage, valid for arbitrary relation between voltage and temperature. Two limits are then treated: a pulse of voltage and a DC voltage. A pulse of voltage causes phase sensitive current fluctuations for which we derive microscopically an expression periodic in ∫ V(t)dt with the period h/e. Applied to current fluctuations in Josephson circuits caused by phase slips, it gives an anomalous contribution to the noise with a logarithmic singularity near the critical current. In the DC case, we get quantum to classical shot noise reduction factor 1/3, in agreement with recent results of Beenakker and Büttiker.