Non-equilibrium noise in a mesoscopic conductor: microscopic analysis
نویسنده
چکیده
Current fluctuations are studied in a mesoscopic conductor using nonequilibrium 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. PACS numbers: 72.10.Bg, 73.50.Fq, 73.50.Td Typeset using REVTEX
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