A profusion of $1/2$ BPS Wilson loops in $\mathcal{N}=4$ Chern-Simons-matter theories

TL;DR

This paper explores the construction and properties of various 1/2 BPS Wilson loops in 3D N=4 Chern-Simons-matter theories, revealing new degeneracies, enlargements, and quantum behaviors, with implications for their dual M-theory descriptions.

Contribution

It introduces a comprehensive classification of 1/2 BPS Wilson loops in N=4 Chern-Simons-matter theories, including cases with vanishing Chern-Simons levels and their quantum properties.

Findings

Pairs of Wilson loops associated with quiver nodes are identified.

Wilson loops with vanishing Chern-Simons levels are enlarged to 1/2 BPS.

Some Wilson loops are cohomologically equivalent to 1/4 BPS loops.

Abstract

We initiate the study of $1/2$ BPS Wilson loops in $\mathcal{N}=4$ Chern-Simons-matter theories in three dimensions. We consider a circular or linear quiver with Chern-Simons levels $k$, $-k$ and $0$, and focus on loops preserving one of the two $SU(2)$ subgroups of the $R$-symmetry. In the cases with no vanishing Chern-Simons levels, we find a pair of Wilson loops for each pair of adjacent nodes on the quiver connected by a hypermultiplet (nodes connected by twisted hypermultiplets have Wilson loops preserving another set of supercharges). We expect this classical pairwise degeneracy to be lifted by quantum corrections. In the case with nodes with vanishing Chern-Simons terms connected by twisted hypermultiplets, we find that the usual $1/4$ BPS Wilson loops are automatically enlarged to $1/2$ BPS, as happens also in 3-dimensional Yang-Mills theory. When the nodes with vanishing Chern-Simons levels are connected by untwisted hypermultiplets, we do not find any Wilson loops coupling to those nodes which are classically invariant. Rather, we find several loops whose supersymmetry variation, while non zero, vanishes in any correlation function, so is weakly zero. We expect only one linear combination of those Wilson loops to remain BPS when quantum corrections are included. We analyze the M-theory duals of those Wilson loops and comment on their degeneracy. We also show that these Wilson loops are cohomologically equivalent to certain $1/4$ BPS Wilson loops whose expectation value can be evaluated by the appropriate localized matrix model.