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TT: Fachverband Tiefe Temperaturen

TT 42: Correlated Electrons: Low-dimensional Systems - Models 2

TT 42.1: Vortrag

Donnerstag, 26. März 2009, 14:00–14:15, HSZ 301

Universal dephasing in a chiral 1D interacting Fermion system — •Clemens Neuenhahn and Florian Marquardt — Department of Physics, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig Maximilians Universität München

We consider dephasing by interparticle interactions in a one-dimensional chiral Fermion system[1]. Such systems are realized by the edge states in the integer Quantum Hall Effect, which are used for the experimental realization of an electronic Mach-Zehnder interferometer. We calculate the spatial decay of the single particle Green’s function for fixed energy, which determines the interference contrast of the interferometer. Thereby, the finite range of the interaction potential is taken into account. Drawing on both the known exact bosonization solution and a physically transparent semiclassical approach, we show that at high energies the asymptotic decay of the Green’s function with increasing propagation length becomes universal: At zero temperature, for smooth interaction potentials, we obtain a power-law decay with an exponent 1, independent of the interaction strength. We comment on how the non-interacting limit is recovered and obtain the dephasing rate at finite temperature. Introducing an effective noise spectrum acting on the propagating electron, we address the physical mechanism of decoherence in the high-energy limit. [1] C. Neuenhahn and F. Marquardt, arXiv:0806.1211 (2008).