A Fueter operator for 3/2-spinors
Ahmad Reza Haj Saeedi Sadegh, Minh Lam Nguyen
TL;DR
This work investigates the non-compactness of moduli spaces for generalized Seiberg–Witten-type equations with $3/2$-spinors on closed 3-manifolds by introducing a 3/2-Fueter operator $\mathfrak{Q}$. The authors construct an aquaternionic moduli space $W_0$, a 4-dimensional fiber over the base, via hyperkähler reduction, and define $\mathfrak{Q}$ as the projection of the Fueter operator to a natural normal bundle. A Haydys-type correspondence is established: solutions to the degenerate RS-SW equations are in one-to-one correspondence with solutions of $\mathfrak{Q}$, yielding a nonlinear, overdetermined elliptic operator. The overdetermination implies potential obstructions to compactness in certain geometries and points toward new 3-manifold invariants derived from RS-type operators, with broader implications for gauged-sigma models and hyperkähler geometry.
Abstract
We show the non-compactness of moduli space of solutions of the monopole equations for $3/2$-spinors on a closed 3-manifold is equivalent to the existence of `3/2-Fueter sections' that are solutions of an overdetermined non-linear elliptic differential equation. These are sections of a fiber bundle whose fiber is a special 4-dimensional submanifold of the hyperkähler manifold of center-framed charged one $SU(2)$-instantons on $\mathbf{R}^4$. This fiber bundle does not inherit a hyperkähler structure.
