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TT: Fachverband Tiefe Temperaturen

TT 20: Transport: Quantum Coherence and Quantum Information Systems 3 (jointly with MA and HL)

TT 20.8: Talk

Tuesday, March 27, 2012, 12:00–12:15, BH 243

Noise-induced transition in an electronic Mach-Zehnder interferometer — •Andreas Helzel¹, Leonid Litvin¹, Werner Wegscheider², and Christoph Strunk¹ — ¹Institute of exp. and applied physics, University of Regensburg, Germany — ²Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland

The visibility of Aharonov-Bohm interference of an electronic Mach-Zehnder interferometer (MZI) shows a lobe structure when changing the applied DC bias. Multiple side lobes are present at filling factors from 1.5 to 2. By varying the transmission of a quantum point contact set in series at a distance D before the MZI (QPC0) we can suppress the multiple side lobes to a single side lobe. This occurs at a transmission probability of T_QPC0=0.5. Above this transmission the lobe structure is robust and does not change qualitatively. For T_QPC0<0.5 the multiple side lobes disappear and the central lobe width increases drastically with decreasing transmission. We see these properties both in the visibility and in the AB-phase. This behavior coincides with a recently proposed noise-induced phase transition [1].
Ivan P. Levkivskyi, Eugene V. Sukhorukov, Phys. Rev. Lett. 103, 036801 (2009)