Electromagnetic Response and Approximate SO(5) Symmetry in High-Tc Superconductors

TL;DR

This paper investigates the electromagnetic properties of high-Tc cuprate superconductors, highlighting how approximate SO(5) symmetry influences optical and Raman responses through pseudo Goldstone bosons.

Contribution

It demonstrates the potential large optical and Raman responses in the antiferromagnetic phase due to approximate SO(5) symmetry and pseudo Goldstone bosons.

Findings

Large optical conductivities predicted in the AF phase

Enhanced Raman scattering rates due to bosonic excitations

Constraints on boson properties like mass gap and velocity

Abstract

It has been proposed that the effective Hamiltonian describing high T_c superconductivity in cuprate materials has an approximate SO(5) symmetry relating the superconducting (SC) and antiferromagnetic (AF) phases of these systems. We show that robust consequences of this proposal are potentially large optical conductivities and Raman scattering rates in the AF phase, due to the electromagnetic response of the doubly-charged pseudo Goldstone bosons which must exist there. This provides strong constraints on the properties of the bosons, such as their mass gap and velocity.