1. Quantum Measurement Group, MIT, Cambridge, Massachusetts, USA
2. School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
3. Department of Physics, MIT, Cambridge, Massachusetts, USA
4. Department of Mechanical Engineering, MIT, Cambridge, Massachusetts, USA
5. Department of Chemistry, MIT, Cambridge, Massachusetts, USA
6. Department of Electrical Engineering and Computer Science, MIT, Cambridge, Massachusetts, USA
7. Department of Nuclear Science and Engineering, MIT, Cambridge, MA, USA
8. Department of Physics and Astronomy, Clemson University, Clemson, South Carolina, USA