Phonon-induced decoherence and dissipation in donor-based charge qubits |
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Authors: | J Eckel S Weiss M Thorwart |
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Institution: | 1. Institut für Theoretische Physik IV, Heinrich-Heine-Universit?t Düsseldorf, 40225, Düsseldorf, Germany
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Abstract: | We investigate the phonon-induced decoherence and dissipation in a
donor-based charge quantum bit realized by the orbital states of an
electron shared by two dopant ions which are implanted in a
silicon host crystal. The dopant ions are taken from the group-V
elements Bi, As, P, Sb. The excess electron is
coupled to deformation potential acoustic phonons which dominate in
the Si host. The particular geometry tailors a non-monotonous frequency
distribution of the phonon modes. We determine the exact qubit dynamics
under the influence of the phonons by employing
the numerically exact
quasi-adiabatic propagator path integral scheme thereby taking
into account all bath-induced correlations. In particular, we
have improved the scheme by completely eliminating the Trotter
discretization error by a Hirsch-Fye extrapolation. By comparing
the exact results to those of a Born-Markov
approximation we find that the latter yields appropriate estimates for
the decoherence and relaxation rates. However, noticeable quantitative
corrections due to non-Markovian contributions appear. |
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Keywords: | 03 67 Lx Quantum computation 63 20 Kr Phonon-electron and phonon-phonon interactions 03 65 Yz Decoherence open systems quantum statistical methods |
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