Charge qubit dynamics in a double quantum dot coupled to phonons

Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China(Dated: February 2, 2008)The dynamics of charge qubit in a double quantum dot coupled to phonons is investigated the-oretically in terms of a perturbation treatment based on a unitary transformation. The dynamicaltunneling current is obtained explicitly. The result is compared with the standard perturbation the-ory at Born-Markov approximation. The decoherence induced by acoustic phonons is analyzed atlength. It is shown that the contribution from deformation potential coupling is comparable to thatfrom piezoelectric coupling in small dot size and large tunneling rate case. A possible decouplingmechanism is predicted.