Phonon Decoherence of a Double Quantum Dot Charge Qubit

The decoherence of a lateral double quantum dot charge qubit due to coupling to piezoelectric acoustic phonons has been investigated within the Born-Markov approximation. After including appropriate form factors, we have found that phonon decoherence rates are one to two orders of magnitude weaker than earlier predictions based on the spin-boson model. We have calculated the dependence of the Q-factor on lattice temperature, quantum dot size, and interdot coupling. Our results suggest that mechanisms other than phonon decoherence play a more significant role in current experimental setups.