The Exact Effective Couplings of 4D N=2 gauge theories

TL;DR

This paper derives exact effective couplings for 4D N=2 gauge theories, enabling the computation of operator anomalous dimensions by replacing the N=4 coupling with an interpolating effective coupling, using localization and holography.

Contribution

It introduces a method to determine exact effective couplings in N=2 theories, extending N=4 results via localization and holographic duality, and interprets these as finite renormalizations.

Findings

Computed weak coupling expansions of effective couplings.

Determined leading strong coupling behavior.

Linked effective couplings to string tensions in gravity duals.

Abstract

The anomalous dimensions of operators in the purely gluonic SU(2,1|2) sector of any planar conformal N=2 theory can be read off from the N=4 SYM results by replacing the N=4 coupling constant by an interpolating function of the N=2 coupling constants, to which we refer to as the effective coupling. For a large class of N=2 theories we compute the weak coupling expansion of these functions as well as the leading strong coupling term by employing supersymmetric localization. Via Feynman diagrams, we interpret our results as the relative (between N=2 and N=4) finite renormalization of the coupling constant. Using the AdS/CFT dictionary, we identify the effective couplings with the effective string tensions of the corresponding gravity dual theories. Thus, any observable in the SU(2,1|2) sector can be obtained from its N=4 counterpart by replacing the N=4 coupling constant by the universal, for a given theory, effective coupling.