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

M. Thorwart·J. Eckel·E. R. Mucciolo
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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 a 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.

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M. Thorwart, J. Eckel, E. R. Mucciolo. 2005-10-24. Non-Markovian dynamics of double quantum dot charge qubits due to acoustic phonons. https://doi.org/10.1103/physrevb.72.235320

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