1. Institute of Physics (IA) RWTH Aachen University 52056 Aachen Germany
2. Department of Mechanical Engineering Vanderbilt University 2400 Highland Ave Nashville TN 37212 USA
3. Quantum Information Science Group Oak Ridge National Laboratory 1 Bethel Valley Rd Oak Ridge TN 37830 USA
4. US Naval Research Laboratory 4555 Overlook Ave, S.W. Washington, DC 20375 USA
5. Department of Materials Science and Engineering McMaster University Hamilton ON L8S 4L8 Canada