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TT: Fachverband Tiefe Temperaturen

TT 3: Transport: Fluctuations and Noise

TT 3.10: Talk

Monday, February 25, 2008, 12:30–12:45, H 2053

Decoherence by Quantum Telegraph Noise — •Benjamin Abel and Florian Marquardt — Arnold-Sommerfeld Center for Theoretical Physics, Center for NanoScience and Department of Physics, Ludwig-Maximilians Universität München, Munich, Germany

We investigate the time-evolution of the density matrix of a charge qubit subject to quantum telegraph noise, produced by a single electronic defect level. We obtain strikingly different results for the time-evolution of the coherence from the case of Gaussian noise. Depending on the coupling strength of the qubit to the heat-bath and temperature we observe a qualitatively different behavior of the coherence. We simulated spin-echo sequences and discuss the time-evolution of the echo signal. Our analysis relies on a numerical evaluation of the exact solution for the density matrix of the qubit.