Period doubling in the 2D Antiferromagnet. New gauge-fields and their anomalies

TL;DR

This paper develops an effective gauge field theory for a 2D quantum antiferromagnet with period doubling, revealing new gauge fields and anomalies that influence flux configurations and enforce single occupancy.

Contribution

It introduces a novel gauge field model accounting for period doubling and identifies a new quantum anomaly affecting flux and occupancy constraints.

Findings

Identification of four gauge fields due to period doubling

Discovery of a new quantum anomaly in the model

Numerical validation of the generalized flux hypothesis

Abstract

We construct an effective gauge field theory model describing a 2D quantum antiferromagnet in the flux phase ground state. Due to period doubling the number of gauge fields is four rather than the naively expected single one. These additional gauge fields correspond to field configurations in which the flux is staggered, which should be taken into account to enforce single occupancy within the magnetic unit cell. We calculate a new type of quantum anomaly, present in such a model. In particular this leads to a generalized local flux hypothesis, which is tested numerically.