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

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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.
5 pages, 7 figures, replaced with the version to appear in Phys. Rev. B

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Mesoscale and Nanoscale Physics, Quantum Physics

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http://salesiana.dossiersoluciones.com/handle/123456789/100536

Consulte el texto completo en el siguiente enlace:

https://arxiv.org/abs/cond-mat/0505621
 http://arxiv.org/abs/cond-mat/0505621
 Phys. Rev. B. 72, 235320 (2005)
 doi:10.1103/PhysRevB.72.235320

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