1. ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
2. Quantum Institute for Light and Atoms, Department of Physics, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
3. ICREA – Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain