An $\mathcal{N}=1$ 3d-3d Correspondence
Julius Eckhard, Sakura Schafer-Nameki, Jin-Mann Wong
TL;DR
This paper proposes an $ ext{N}=1$ 3d--3d correspondence arising from M5-branes on associative three-cycles in $G_2$-manifolds, relating $T_{ ext{N}=1}[M_3]$ to two topological theories: BFH on $M_3$ for the Witten index and CS–Dirac on $M_3$ for the $S^3$-partition function. The Witten index is computed as the Euler character of the moduli space of generalized Seiberg–Witten solutions, with abelian checks and Lens-space refinements; the $S^3$-partition function is captured by CS–Dirac theory, which reduces to real Chern–Simons or WRT-type invariants depending on twisted harmonic spinors. A non-abelian generalization is explored via circle reductions to 2d sigma-models and Lens-space reductions, while the Lens-space case yields tractable checks against known invariants. The work connects M5-brane dynamics, associative-calibrated geometry, and topological field theories to provide a framework for $ ext{N}=1$ observables in three dimensions, with potential extensions to holography and $ ext{N}=1$ AGT-type correspondences.
Abstract
M5-branes on an associative three-cycle $M_3$ in a $G_2$-holonomy manifold give rise to a 3d $\mathcal{N}=1$ supersymmetric gauge theory, $T_{\mathcal{N}=1} [M_3]$. We propose an $\mathcal{N}=1$ 3d-3d correspondence, based on two observables of these theories: the Witten index and the $S^3$-partition function. The Witten index of a 3d $\mathcal{N}=1$ theory $T_{\mathcal{N}=1} [M_3]$ is shown to be computed in terms of the partition function of a topological field theory, a super-BF-model coupled to a spinorial hypermultiplet (BFH), on $M_3$. The BFH-model localizes on solutions to a generalized set of 3d Seiberg-Witten equations on $M_3$. Evidence to support this correspondence is provided in the abelian case, as well as in terms of a direct derivation of the topological field theory by twisted dimensional reduction of the 6d $(2,0)$ theory. We also consider a correspondence for the $S^3$-partition function of the $T_{\mathcal{N}=1} [M_3]$ theories, by determining the dimensional reduction of the M5-brane theory on $S^3$. The resulting topological theory is Chern-Simons-Dirac theory, for a gauge field and a twisted harmonic spinor on $M_3$, whose equations of motion are the generalized 3d Seiberg-Witten equations. For generic $G_2$-manifolds the theory reduces to real Chern-Simons theory, in which case we conjecture that the $S^3$-partition function of $T_{\mathcal{N}=1}[M_3]$ is given by the Witten-Reshetikhin-Turaev invariant of $M_3$.
