Interaction Round a Face DMRG method applied to rotational invariant quantum spin chains

TL;DR

This paper introduces an IRF-DMRG method tailored for rotationally invariant higher-spin chains, enabling efficient calculation of Haldane gaps and ground state energies with limited states.

Contribution

The paper develops a novel IRF-DMRG approach specifically for higher integer spin chains with rotational symmetry, providing explicit IRF weights and accurate results.

Findings

Accurately computed Haldane gaps for S=1 and S=2 chains.

Efficient calculation with only 90 states kept.

Validated method for rotationally invariant quantum spin models.

Abstract

An interaction-round-a-face density-matrix renormalization-group (IRF-DMRG) method is developed for higher integer spin chain models which are rotational invariant. The expressions of the IRF weights associated with the nearest-neighbor spin-S interaction ${\bf S}_{i} \cdot {\bf S}_{i+1}$ are derived explicitly. Using the IRF-DMRG with these IRF weights, the Haldane gaps $\Delta$ and the ground state energy densities $e_{0}$ for both S=1 and S=2 isotropic antiferromagnetic Heisenberg quantum spin chains are calculated by keeping up to only m=90 states.