Noise-induced phase transition in the electronic Mach-Zehnder interferometer.
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 of 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.
Levkivskyi
Ivan P
IP
Département de Physique Théorique, Université de Genève, CH-1211 Genève 4, Switzerland.
Sukhorukov
Eugene V
EV