Instituto de Ciencia de Materiales de Madrid
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Non-Markovian qubit decoherence during dispersive readout

Georg M. Reuther, Peter Hänggi, and Sigmund Kohler
Phys. Rev. A 85, 062123 (2012)

We study qubit decoherence under generalized dispersive readout, i.e., we investigate a qubit coupled to a resonantly driven dissipative harmonic oscillator. We provide a complete picture by allowing for arbitrarily large qubit-oscillator detuning and by considering also a coupling to the square of the oscillator coordinate, which is relevant for flux qubits. Analytical results for the decoherence time are obtained by a transformation of the qubit-oscillator Hamiltonian to the dispersive frame and a subsequent master equation treatment beyond the Markov limit. We predict a crossover from Markovian decay to a decay with Gaussian shape. Our results are corroborated by the numerical solution of the full qubit-oscillator master equation in the original frame.
arXiv:1205.2315 [cond-mat]

[ICMM-CSIC] [Condensed Matter Theory]
last modified: 18.6.2018 by Sigmund Kohler