Indirect stabilization of N -level quantum systems

We study the stabilizability of a N -level quantum systems using an indirect control ar- chitecture mediated by a noisy ancilla. After outlining the general theoretical framework for arbitrary N , we focus on the two-level case (N = 2), for which we derive a complete set of necessary and sufficient conditions for asymptotic stability. Finally, we illustrate the analyti- cal results with a simple numerical example on a two-spin system, showing convergence to a Bell state for a set of random initial conditions.