We investigate the time-evolution of a charge qubit subject to quantum telegraph noise produced by a single electronic defect level. We obtain results for the time-evolution of the coherence that are strikingly different from the usual case of a harmonic oscillator bath (Gaussian noise). When the coupling strength crosses a certain temperature-dependent threshold, we observe coherence oscillations in the strong-coupling regime. Moreover, we present the time-evolution of the echo signal in a spin-echo experiment. Our analysis relies on a numerical evaluation of the exact solution for the density matrix of the qubit.
@article{arxiv.0805.0962,
title = {Decoherence by Quantum Telegraph Noise},
author = {Benjamin Abel and Florian Marquardt},
journal= {arXiv preprint arXiv:0805.0962},
year = {2008}
}