Phonon-induced decoherence for a quantum-dot spin qubit operated by Raman passage

We study single-qubit gates performed via stimulated Raman adiabatic passage on a spin qubit implemented in a quantum-dot system in the presence of phonons. We analyze the interplay of various kinds of errors resulting from the carrier-phonon interaction (including also the effects of spin-orbit coupling) as well as from quantum jumps related to nonadiabaticity and calculate the fidelity as a function of the pulse parameters. We give quantitative estimates for an InAs∕GaAs system and identify the parameter values for which the error is considerably minimized, even to values below 10^-4 per operation.