About the Authors
Center for Theoretical Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, People's Republic of China
The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, People's Republic of China
Department of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong, Special Administrative Region, People's Republic of China
The authors have declared that no competing interests exist.
Conceived and designed the experiments: YW QO. Performed the experiments: YW XZ JY. Analyzed the data: YW QO. Wrote the paper: YW QO.