Quantum stochastic processes in mesoscopic conductors

We show an equivalence between the approach of Buttiker and the Fermi quantum stochastic calculus for mesoscopic systems. To illustrate the method we derive the current fluctuations in a two terminal mesoscopic circuit with two tunnel barriers containing a single quasi bound state on the well. The method enables us to focus on either the incoming/outgoing Fermi fields in the leads, or on the irreversible dynamics of the well state itself. The quantum stochastic calculus we use is the Fermi analogue of the input/output methods of quantum optics.