While the existence of a chiral spin liquid (CSL) on a class of spin-1/2 kagome antiferromagnets is by now well-established numerically, a controlled theoretical path from the lattice model leading to a low energy topological field theory is still lacking. This we provide via an explicit construction, starting from reformulating a microscopic model for a CSL as a lattice gauge theory, and deriving the low-energy form of its continuum limit. A crucial ingredient is the realisation that the bosonic spinons of the gauge theory exhibit a U(1) symmetry-protected topological (SPT) phase, which upon promoting its U(1) global symmetry to a local gauge structure ("gauging") yields the CSL. We suggest that such an explicit lattice-based construction involving gauging of an SPT phase can be applied more generally to understand topological spin liquids.
@article{arxiv.1509.03070,
title = {Kagome chiral spin liquid as a gauged U(1) symmetry protected topological phase},
author = {Yin-Chen He and Subhro Bhattacharjee and Frank Pollmann and R. Moessner},
journal= {arXiv preprint arXiv:1509.03070},
year = {2016}
}