Full counting-statistics in a single-electron transistor in the presence of nonequilibrium quantum fluctuations of charge

Institut fu¨r Theoretische Festk¨operphysik, Universit¨at Karlsruhe, 76128 Karlsruhe, Germany(Dated: February 2, 2008)Using the Schwinger-Keldysh approach and the drone (Majorana) fermion representation, weevaluate current distribution in a single-electron transistor in a regime where a total tunnelresistanceis small. Nonequilibrium quantum fluctuations of charge induce a lifetime broadening of charge-state level, as well as renormalization of system parameters. We find that the lifetime broadeningeffect may suppress the probability of relatively large current.