Topological Degeneracy of Quantum Hall Fluids

TL;DR

This paper introduces a universal method to compute the ground state degeneracy of non-abelian quantum Hall liquids on a torus, applicable to various theories including those not described by non-abelian Chern-Simons models.

Contribution

It presents a new approach to analyze the ground state structure of non-abelian quantum Hall liquids, including those beyond known effective theories, using lattice points within folded unit cells.

Findings

Reproduces known results for non-abelian Chern-Simons theories.

Describes ground states as points on a lattice inside folded unit cells.

Provides a classification scheme for non-abelian QH liquids from the parton construction.

Abstract

We present a simple approach to calculate the degeneracy and the structure of the ground states of non-abelian quantum Hall (QH) liquids on the torus. Our approach can be applied to any QH liquids (abelian or non-abelian) obtained from the parton construction. We explain our approach by studying a series of examples of increasing complexity. When the effective theory of a non-abelian QH liquid is a non-abelian Chern-Simons (CS) theory, our approach reproduces the well known results for the ground state degeneracy of the CS theory. However, our approach also apply to non-abelian QH liquids whose effective theories are not known and which cannot be written as a non-abelian CS theory. We find that the ground states on a torus of all non-abelian QH liquids obtained from the parton construction can be described by points on a lattice inside a "folded unit cell." The folding is generated by reflection, rotations, etc. Thus the ground state structures on the torus described by the ``folded unit cells'' provide a way to (at least partially) classify non-abelian QH liquids obtained from the parton construction.