Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 73: Fluctuations and Noise
TT 73.1: Vortrag
Freitag, 15. März 2013, 11:45–12:00, H20
Noise-induced Phase Transition in an Electronic Mach-Zehnder Interferometer: a Manifestation of Non-Gaussian Noise — Andreas Helzel1, Leonid V. Litvin1, Ivan P. Levkivskyi2, 3, Eugene V. Sukhorukov2, Werner Wegscheider4, and •Christoph Strunk1 — 1Institut für experimentelle und angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — 2Département de Physique Théorique, Université de Genève, CH-1211 Genève 4, Switzerland — 3Bogolyubov Institute for Theoretical Physics, 03680 Kiev, Ukraine — 4Laboratorium für Festkörperphysik, HPF E 7, ETH Zürich, 8093 Zürich, Switzerland
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 T0 of the QPC, and changes qualitatively at T0=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 T0<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 T0=1/2.