Non-Markovian dynamics of double quantum dot charge qubits due to acoustic phonons

    Authors

    M. Thorwart; J. Eckel;E. R. Mucciolo

    Comments

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    Abbreviated Journal Title

    Phys. Rev. B

    Keywords

    REDUCED DENSITY-MATRICES; DISSIPATIVE SYSTEMS; TENSOR PROPAGATOR; TIME; EVOLUTION; LONG-TIME; COHERENT; Physics, Condensed Matter

    Abstract

    We investigate the dynamics of a double quantum dot charge qubit which is coupled to piezoelectric acoustic phonons, appropriate for GaAs heterostructures. At low temperatures, the phonon bath induces the non-Markovian dynamical behavior of the oscillations between the two charge states of the double quantum dot. Upon applying the numerically exact quasiadiabatic propagator path-integral scheme, the reduced density matrix of the charge qubit is calculated, thereby avoiding the Born-Markov approximation. This allows a systematic study of the dependence of the Q factor on the lattice temperature, on the size of the quantum dots, as well as on the interdot coupling. We calculate the Q factor for a recently realized experimental setup and find that it is two orders of magnitudes larger than the measured value, indicating that the decoherence due to phonons is a subordinate mechanism.

    Journal Title

    Physical Review B

    Volume

    72

    Issue/Number

    23

    Publication Date

    1-1-2005

    Document Type

    Article

    Language

    English

    First Page

    6

    WOS Identifier

    WOS:000234336000076

    ISSN

    1098-0121

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