U(1) Gauge Theory of the Heisenberg Antiferromagnet

Abstract

The low-energy spin excitations in the flux phase of the (2+1)-dimensional large-$n$ $\mathrm{SU}\mathrm{}\left(n\right)\mathrm{}$Heisenberg antiferromagnet are relativistic fermions coupled to a U(1) gauge field. These excitations are studied in the physical $n=2\mathrm{}$ case with the use of a $\frac{1}{n}$ expansion. A Chern-Simons term is included to remove gauge configurations forbidden in the $n=2\mathrm{}$ theory.