Systematic Low-Energy Effective Theory for Magnons and Charge Carriers in an Antiferromagnet

TL;DR

This paper develops a universal, systematic low-energy effective field theory for magnons and charge carriers in antiferromagnets, providing model-independent predictions relevant to high-temperature superconductors.

Contribution

It introduces a novel effective theory for magnons and electrons/holes in antiferromagnets, analogous to chiral perturbation theory, with detailed symmetry analysis and electromagnetic coupling.

Findings

Constructed a comprehensive effective action for magnons and charge carriers.

Analyzed symmetries of the Hubbard model within the effective theory.

Explored electromagnetic interactions in the low-energy regime.

Abstract

By electron or hole doping quantum antiferromagnets may turn into high-temperature superconductors. The low-energy dynamics of antiferromagnets are governed by their Nambu-Goldstone bosons -- the magnons -- and are described by an effective field theory analogous to chiral perturbation theory for the pions in strong interaction physics. In analogy to baryon chiral perturbation theory -- the effective theory for pions and nucleons -- we construct a systematic low-energy effective theory for magnons and electrons or holes in an antiferromagnet. The effective theory is universal and makes model-independent predictions for the entire class of antiferromagnetic cuprates. We present a detailed analysis of the symmetries of the Hubbard model and discuss how these symmetries manifest themselves in the effective theory. A complete set of linearly independent leading contributions to the effective action is constructed. The coupling to external electromagnetic fields is also investigated.