Fermionic Mach-Zehnder interferometer subject to a quantum bath

• Published in: Europhysics letters Vol. 72; no. 5; pp. 788 - 794
• Main Author: Marquardt, F
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.12.2005; EDP Sciences
• Subjects: 03.65.Yz; 72.70.+m; 73.23.-b
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i2005-10310-1

We study fermions in a Mach-Zehnder interferometer, subject to a quantum-mechanical environment leading to inelastic scattering, decoherence, renormalization effects, and time-dependent conductance fluctuations. We present a method to derive both the loss of interference contrast as well as the shot noise, using equations of motion and leading-order perturbation theory. The dependence of the shot noise on the Aharonov-Bohm phase acquires an unexpected average phase shift, due to correlations between the fluctuating renormalized phase shift and the output current. We discuss the limiting behaviours at low and high voltages, compare with simpler models of dephasing, and present implications for experiments.