Spinon confinement and the Haldane gap in SU(n) spin chains

TL;DR

This paper uses DMRG calculations to demonstrate that the classification of SU(n) spin chains based on spinon confinement and the Haldane gap, previously established for valence bond solid models, also applies to SU(n) Heisenberg chains, highlighting the role of next-nearest neighbor interactions.

Contribution

It extends the classification of SU(n) spin chains regarding spinon confinement and the Haldane gap to SU(n) Heisenberg models using numerical methods.

Findings

Spinon confinement observed in SU(4) chain with next-nearest neighbor interaction.

Classification from valence bond solid models applies to Heisenberg chains.

Next-nearest neighbor interactions induce a Haldane gap.

Abstract

We use extensive DMRG calculations to show that a classification of SU(n) spin chains with regard to the existence of spinon confinement and hence a Haldane gap obtained previously for valence bond solid models applies to SU(n) Heisenberg chains as well. In particular, we observe spinon confinement due to a next-nearest neighbor interaction in the SU(4) representation 10 spin chain.