About the Authors

Chao-Qing Dai

dcq424@126.com

Affiliations School of Sciences, Zhejiang Agriculture and Forestry University, Lin'an, Zhejiang, P.R.China, Optical Sciences Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT, Australia

Yan Wang

Affiliation Institute of Theoretical Physics, Shanxi University, Taiyuan, P.R.China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Analyzed the data: CQD YW. Contributed reagents/materials/analysis tools: CQD YW. Contributed to the writing of the manuscript: CQD. Designed the software used in analysis, generating solutions, visualizing some of the solutions: CQD. Discussed and polished the manuscript: YW. Read and approved the manuscript: CQD YW.