Statistics of current fluctuations in mesoscopic coherent conductors at nonzero frequencies

Abstract

We formulate a general approach which describes statistics of current\nfluctuations in mesoscopic coherent conductors at arbitrary frequencies and in\nthe presence of interactions. Applying this approach to the non-interacting\ncase, we analyze frequency dispersion of the third cumulant of the current\noperator ${\\cal S}_3$ at frequencies well below both the inverse charge\nrelaxation time and the inverse electron dwell time. This dispersion turns out\nto be important in the frequency range comparable to applied voltages. For\ncomparatively transparent conductors it may lead to the sign change of ${\\cal\nS}_3$\n