[1] Univ Maryland, Condensed Matter Theory Ctr, College Pk, MD 20742 USA
[2] Univ Maryland, Joint Quantum Inst, Dept Phys, College Pk, MD 20742 USA
[3] Wuhan Univ, Sch Phys & Technol, Wuhan 430072, Peoples R China
[4] Wuhan Inst Quantum Technol, Wuhan 430206, Peoples R China