Jeudi 11 février 2016 à 10h15
Salle 234, Ecole de Physique

Full counting statistics as a quasi-probability distribution

Patrick Hofer, University of Geneva

The full counting statistics describes the fluctuations of a time-integrated quantum observable, most notably the charge transferred through mesoscopic conductors. While it is well known that this distribution can fail to be positive, the interpretation and origin of this negativity has been somewhat unclear. Here, we show how the full counting statistics can be tied to trajectories through Hilbert space, and how this directly connects negative quasi-probabilities to an unusual interference effect. Our approach sheds light on the dynamics of quantum systems and on the influence of measurement devices, which are ultimately described by positive probability distributions.