Spin $j$ Dirac Operators on the Fuzzy 2-Sphere

TL;DR

This paper constructs and analyzes spin j Dirac operators on the fuzzy 2-sphere, establishing criteria for their continuum limit, and explores their instanton sectors and index theory.

Contribution

It generalizes the construction of Dirac operators for arbitrary spin j on the fuzzy 2-sphere and studies their continuum limits and topological properties.

Findings

Identified preferred fuzzy Dirac operators with proper continuum limit

Formulated instanton sectors and index theory for these operators

Extended analysis to arbitrary spin j on the fuzzy 2-sphere

Abstract

The spin 1/2 Dirac operator and its chirality operator on the fuzzy 2-sphere $S^2_F$ can be constructed using the Ginsparg-Wilson(GW) algebra [arxiv:hep-th/0511114]. This construction actually exists for any spin $j$ on $S^2_F$, and have continuum analogues as well on the commutative sphere $S^2$ or on $\mathbb{R}^{2}$. This is a remarkable fact and has no known analogue in higher dimensional Minkowski spaces. We study such operators on $S^2_F$ and the commutative $S^2$ and formulate criteria for the existence of the limit from the former to the latter. This singles out certain fuzzy versions of these operators as the preferred Dirac operators. We then study the spin 1 Dirac operator of this preferred type and its chirality on the fuzzy 2-sphere and formulate its instanton sectors and their index theory. The method to generalize this analysis to any spin $j$ is also studied in detail.