Full Counting Statistics for a Single-Electron Transistor,   Non-equilibrium Effects at Intermediate Conductance
  We evaluate the current distribution for a single-electron transistor with intermediate strength tunnel conductance. Using the Schwinger-Keldysh approach and the drone (Majorana) fermion representation we account for the renormalization of system parameters. Nonequilibrium effects induce a lifetime broadening of the charge-state levels, which suppress large current fluctuations. 
Yasuhiro Utsumi, Dmitri S. Golubev, Gerd Sch\"on