1. School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710072, China
2. School of Electronic Engineering, Xidian University, Xi’an 710071, China
3. Department of Physics, Hebei University, Baoding 071002, China
4. Key Laboratory of High-Precision Computation and Application of Quantum Field Theory of Hebei Province, Baoding 071002, China