A square lattice algebraic spin liquid with SO(5) symmetry

TL;DR

This paper proposes a novel critical spin liquid state with SO(5) symmetry for S=1/2 antiferromagnets on the square lattice, suggesting a potential transition between Neel and valence bond solid phases.

Contribution

It introduces an SO(5) symmetric fixed point arising from perturbations of the staggered flux algebraic spin liquid, linking to the Neel-VBS transition.

Findings

Identification of an SO(5) symmetric fixed point.

Instability of the staggered flux spin liquid towards SO(5) symmetry.

Potential description of the Neel-VBS transition.

Abstract

We propose a critical spin liquid ground state for S=1/2 antiferromagnets on the square lattice. In a renormalization group analysis of the `staggered flux' algebraic spin liquid, we examine perturbations, present in the antiferromagnet, which break its global SU(4) symmetry to SO(5). At physical parameter values, we find an instability towards a fixed point with SO(5) symmetry. We discuss the possibility that this fixed point describes a transition between the Neel and valence bond solid states, and the relationship to the SO(5) non-linear sigma model of Tanaka and Hu.