A semiconductor nanowire quantum dot with strong spin-orbit coupling (SOC) can be used to achieve a spin-orbit qubit. In contrast to a spin qubit, the spin-orbit qubit can respond to an external ac electric field, an effect called electric-dipole spin resonance. Here we develop a theory that can apply in the strong SOC regime. We find that there is an optimal SOC strength \eta_{opt}=\sqrt{2}/2, where the Rabi frequency induced by the ac electric field becomes maximal. Also, we show that both the level spacing and the Rabi frequency of the spin-orbit qubit have periodic responses to the direction of the external static magnetic field. These responses can be used to determine the SOC in the nanowire.
@article{arxiv.1304.3257,
title = {Controlling a Nanowire Spin-Orbit Qubit via Electric-Dipole Spin Resonance},
author = {Rui Li and J. Q. You and C. P. Sun and Franco Nori},
journal= {arXiv preprint arXiv:1304.3257},
year = {2013}
}