1. Department of Physics, Emory University, Atlanta, Georgia, USA; email:
2. BioFrontiers Institute, University of Colorado, Boulder, Colorado, USA
3. Department of Computer Science, University of Colorado, Boulder, Colorado, USA
4. Department of Physics, University of Colorado, Boulder, Colorado, USA
5. Department of Applied Math, University of Colorado, Boulder, Colorado, USA
6. Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA