1. Department of Quantum Matter Physics, University of Geneva, CH-1211 Geneva, Switzerland
2. School of Engineering, University of Applied Sciences of Western Switzerland HES-SO, CH-1951 Sion, Switzerland
3. Automatic Control Laboratory, ETH Zürich, CH-8092 Zürich, Switzerland
4. Center for Control, Dynamical Systems and Computation, UC Santa Barbara, Santa Barbara, California 93106-5070, USA