1211.5951 (A. Helzel et al.)

Noise-induced Phase Transition in an Electronic Mach-Zehnder
Interferometer: a Manifestation of Non-Gaussian Noise    [PDF]

A. Helzel, L. V. Litvin, I. P. Levkivskyi, E. V. Sukhorukov, W. Wegscheider, C. Strunk

An electronic Mach-Zehnder interferometer is employed as a detector for the non-Gaussian current noise emitted from a quantum point contact (QPC). The visibility of Aharonov-Bohm interference in the interferometer constitutes a direct probe of the generator of the full counting statistics (FCS) of the current fluctuations. The visibility shows a lobe and node structure vs. the applied dc bias, which depends on the transmission T of the QPC, and changes qualitatively at T=1/2. The analysis of the data provides direct experimental evidence for a singularity in the FCS. The noise is highly non-Gaussian and leads to an abrupt disappearance of the multiple side lobes for T<1/2. Together with a singularity of the dephasing rate these observations constitute an experimental evidence of a recently predicted noise-induced phase transition occurring at T=1/2.

View original: http://arxiv.org/abs/1211.5951