Infinite Chiral Symmetry in Four Dimensions
Christopher Beem, Madalena Lemos, Pedro Liendo, Wolfger Peelaers, Leonardo Rastelli, Balt C. van Rees
TL;DR
The paper establishes a robust 4d/2d correspondence: a protected, Schur-sector of any four-dimensional N=2 SCFT organizes into a two-dimensional chiral algebra, with Virasoro and affine flavor enhancements tying 4d conformal and flavor anomalies to 2d central charges and levels. This leads to universal constraints on spectra and correlators, concrete realizations in free and Lagrangian theories via BRST reduction, and a framework for understanding non-Lagrangian theories such as class S through chiral algebras and W-algebras. The work also connects chiral-algebra data to the Schur limit of the superconformal index, providing powerful tests in explicit examples (SU(2) SQCD, N=4 SYM, and higher-rank theories) and offering conjectures for the generating structures in various cases. Collectively, the results suggest a deep, algebraic handle on the landscape of N=2 SCFTs and open pathways toward classification via chiral-algebra methods, extending to class S and beyond.
Abstract
We describe a new correspondence between four-dimensional conformal field theories with extended supersymmetry and two-dimensional chiral algebras. The meromorphic correlators of the chiral algebra compute correlators in a protected sector of the four-dimensional theory. Infinite chiral symmetry has far-reaching consequences for the spectral data, correlation functions, and central charges of any four-dimensional theory with ${\mathcal N}=2$ superconformal symmetry.
