A multicritical point of $S = 1$ XXZ chain with single ion anisotropy

Abstract: We research the ground state of the $S = 1$ XXZ spin chain with single ion anisotropy, focusing on XY1, XY2 (Spin Nematic), Neel, Haldane phases. Recently, it was reported that the four phases did not intersect at a single point using conventional numerical methods, which is inconsistent with the bosonization theory. In order to resolve this discrepancy, we propose a unified method to determine phase boundaries by combining conformal field theory (CFT) with numerical diagonalization. And we discuss the symmetry and universality class of the multicritical point.