作者机构:[1]School of Physical Science and Technology, Suzhou University, Suzhou 215006, China, [2]Sehool of Mathematics and Physics, Jiangsu Teachers University of Technology, Changzhou 213001, China
相关基金:Project supported by the National Natural Science Foundation of China (Grant No 10774108).Acknowledgment It is a pleasure to thank Hu Li-Yun, Hao Xiang and Ren Jie for their fruitful discussions about the topic.