Non-Gaussian noise-induced phase transition in the electronic Mach-Zehnder interferometer
Eugene V. Sukhorukov
University of Geneva
Mardi 26/05/2009, 14:00
SPEC Salle Itzykson, Bât.774, Orme des Merisiers
We consider dephasing in the electronic Mach-Zehnder interferometer strongly coupled
to current noise created by a voltage biased quantum point contact (QPC). We find the
visibility of Aharonov-Bohm oscillations as a function voltage bias and express it via
the cumulant generating function of noise. In the large-bias regime, high-order cumulants
of current add up to cancel the dilution effect of a QPC. This leads to an abrupt change in
the dependence of the visibility on voltage bias which occurs at the QPC's transparency T=1/2.
Quantum fluctuations in the vicinity of this point smear out the sharp transition.