Condensed Matter Seminar - Wayne Zheng (The Ohio State University) - Sign Structure, Ground State Degeneracy and Spin Currents in Doped Mott Insulator

In this talk I will discuss some intrinsic properties, namely sign structure and phase string theory in doped Mott insulator, which theoretically is described by t-J model. Also, we investigate the nature of t-J model using exact diagonalization and density matrix renormalization group methods. Persistent spin currents are revealed in the ground states, which are concomitant with a nonzero total momentum or angular momentum associated with the doped hole. The latter determines a nontrivial ground state degeneracy, which also leads to a possible dual picture of various kinds of symmetry breaking orders observed in experiments.