2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/108035The paper discusses various aspects of time-optimal control of quantum spin systems, modelled as right-invariant systems on a compact Lie group G. The main results are the reduction of such a system to an equivalent system on a homogeneous space G/H, and the explicit determination of optimal trajectories on G/H in the case where G/H is a Riemannian symmetric space. These results are mainly obtained by using methods from Lie theory and geometric control.80 pagesQuantum Physicstext