1. School of Mathematics and Computational Science, Hunan First Normal University, Changsha, Hunan 410205, P. R. China
2. Department of Physics, Hunan Normal University, Changsha, Hunan 410081, P. R. China
3. Institute of Applied Mathematics, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, P. R. China
4. Department of Physics, Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081, P. R. China