1. Institue of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
2. LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
3. Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. Departement Physik, Universität Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
5. Université Paris-Saclay, CEA, CNRS, Institut de physique théorique, 91191, Gif-sur-Yvette, France.