  We derive a generalized form of the Electric Dipole Spin Resonance (EDSR)
Hamiltonian in the presence of the spin-orbit interaction for single spins in
an elliptic quantum dot (QD) subject to an arbitrary (in both direction and
magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi
frequency as a function of the magnetic field for sufficiently large Zeeman
energies, and present a microscopic expression for the anisotropic electron
g-tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a
double quantum dot (DQD), where coherent Rabi oscillations between the singlet
and triplet states are induced by jittering the inter-dot distance at the
resonance frequency. Finally, we calculate two-electron-spin relaxation rates
due to phonon emission, for both in-plane and perpendicular magnetic fields.
Our results have immediate applications to current EDSR experiments on nanowire
QDs, g-factor optimization of confined carriers, and spin decay measurements in
DQD spin-orbit qubits.
