1. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
2. Department of Computer Science, Columbia University, New York, NY 10027, United States of America
3. Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
4. Department of Mathematics, Harvard University, Cambridge, MA 02138, United States of America
5. Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
6. Department of Physics, Harvard University, Cambridge, MA 02138, United States of America
7. School of Computer Science, University of Waterloo, Waterloo, ON N2L 3G1, Canada
8. Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America