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

TL;DR

This paper investigates the phase diagram of the $S=1$ XXZ chain with single ion anisotropy, identifying a multicritical point where four phases meet, using a novel combination of conformal field theory and numerical diagonalization.

Contribution

It introduces a unified method combining CFT and numerical diagonalization to accurately locate phase boundaries and analyze the multicritical point.

Findings

Identified a multicritical point where four phases intersect.

Resolved discrepancies between previous numerical results and bosonization theory.

Characterized the symmetry and universality class of the multicritical point.

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.