Excitons in QED3 and spin response in a phase-fluctuating d-wave superconductor

TL;DR

This paper investigates the exciton mode in a QED3 model of a phase-fluctuating d-wave superconductor, deriving conditions for its existence and comparing theoretical dispersion with experimental neutron scattering data.

Contribution

It introduces a Schroedinger-like equation for exciton bound states in QED3 and analyzes their dispersion, linking theory with experimental observations.

Findings

Exciton mode exists below the particle-hole continuum.

Derived conditions for exciton bound state formation.

Compared theoretical dispersion with neutron scattering data.

Abstract

We study the particle-hole exciton mode in the QED3 theory of a phase-fluctuating d-wave superconductor in ladder approximation. We derive a Schroedinger-like equation for the exciton bound state and determine the conditions for its existence. We find the dispersion of this mode below the particle-hole continuum and compare our results with the resonance observed in neutron scattering measurements in cuprates.