Exact Correlators on the Wilson Loop in $\mathcal{N}=4$ SYM: Localization, Defect CFT, and Integrability

TL;DR

This paper computes exact correlation functions on the Wilson loop in N=4 SYM using localization, revealing a topological subsector and connecting to integrability, with results matching string theory at strong coupling and providing new defect CFT data.

Contribution

It introduces a novel method to compute exact correlators on the Wilson loop, linking localization, defect CFT, and integrability in N=4 SYM.

Findings

Correlation functions exhibit a determinant structure and are position-independent.

Results match perturbative string theory calculations at strong coupling.

Reproduction of known generalized Bremsstrahlung functions and finite N extensions.

Abstract

We compute a set of correlation functions of operator insertions on the 1/8 BPS Wilson loop in $\mathcal{N}=4$ SYM by employing supersymmetric localization, OPE and the Gram-Schmidt orthogonalization. These correlators exhibit a simple determinant structure, are position-independent and form a topological subsector, but depend nontrivially on the 't Hooft coupling and the rank of the gauge group. When applied to the 1/2 BPS circular (or straight) Wilson loop, our results provide an infinite family of exact defect CFT data, including the structure constants of protected defect primaries of arbitrary length inserted on the loop. At strong coupling, we show precise agreement with a direct calculation using perturbation theory around the AdS$_2$ string worldsheet. We also explain the connection of our results to the "generalized Bremsstrahlung functions" previously computed from integrability techniques, reproducing the known results in the planar limit as well as obtaining some of their finite N generalizations. Furthermore, we show that the correlators at large N can be recast as simple integrals of products of polynomials (known as Q-functions) that appear in the Quantum Spectral Curve approach. This suggests an interesting interplay between localization, defect CFT and integrability.