Anomalies of Minimal N=(0, 1) and N=(0, 2) Sigma Models on Homogeneous Spaces

TL;DR

This paper investigates chiral anomalies in minimal N=(0,1) and (0,2) sigma models on homogeneous spaces, providing explicit calculations, anomaly cancellation methods, and exploring their implications for model consistency and IR fixed points.

Contribution

It introduces a local anomaly matching condition, relates anomalies to topological constraints, and analyzes how counter-terms affect model flow and fixed points, extending previous work.

Findings

Explicit anomaly calculations for N=(0,1) and (0,2) models

Derivation of a local anomaly matching condition

Identification of conditions for models to flow to superconformal fixed points

Abstract

We study chiral anomalies in $\mathcal N=(0, 1)$ and $(0, 2)$ two-dimensional minimal sigma models defined on generic homogeneous spaces $G/H$. Such minimal theories contain only (left) chiral fermions and in certain cases are inconsistent because of "incurable" anomalies. We explicitly calculate the anomalous fermionic effective action and show how to remedy it by adding a series of local counter-terms. In this procedure, we derive a local anomaly matching condition, which is demonstrated to be equivalent to the well-known global topological constraint on $p_1(G/H)$. More importantly, we show that these local counter-terms further modify and constrain "curable" chiral models, some of which, for example, flow to nontrivial infrared superconformal fixed point. Finally, we also observe an interesting relation between $\mathcal N=(0, 1)$ and $(0, 2)$ two-dimensional minimal sigma models and supersymmetric gauge theories. This paper generalizes and extends the results of our previous publication arXiv:1510.04324.