Microscopic Electron Models with Exact SO(5) Symmetry

TL;DR

This paper develops microscopic electron models exhibiting exact SO(5) symmetry, linking antiferromagnetic and d-wave superconducting states, and explores their phase diagrams and excitations.

Contribution

It introduces a class of models with exact SO(5) symmetry, providing a detailed analysis of their excitations and phase structure.

Findings

Exact correspondence between excitations in both phases

Classification of symmetry-breaking terms

Phase diagram matches SO(5) nonlinear sigma model

Abstract

We construct a class of microscopic electron models with exact SO(5) symmetry between antiferromagnetic and d-wave superconducting ground states. There is an exact one-to-one correspondence between both single-particle and collective excitations in both phases. SO(5) symmetry breaking terms can be introduced and classified according to irreducible representations of the exact SO(5) algebra. The resulting phase diagram and collective modes are identical to that of the SO(5) nonlinear sigma model.