Three-dimensional topological field theory and symplectic algebraic geometry I
Anton Kapustin, Lev Rozansky, Natalia Saulina
TL;DR
The paper develops a comprehensive framework for boundary conditions and defects in the Rozansky–Witten theory, showing that boundary data correspond to complex Lagrangian submanifolds with Calabi–Yau fibrations and that the collection of boundary conditions forms a 2‑category whose morphisms are boundary line operators. Through circle and interval reductions, it reveals deep connections to curved and Landau–Ginzburg variants of the B‑model, and introduces a curved B‑model on boundary data to capture quantum corrections and deformations via curvings and the Atiyah class. The boundary–bulk map generalizes Chern characters to a categorified setting, while line and surface operators organize into a rich monoidal 2‑categorical structure that encodes fusion, braiding, and higher morphisms, with reductions to Landau–Ginzburg theories at intersections. The work ties these physical constructions to categorified algebraic geometry, proposing a framework in which 2‑categories of fibrations over a fixed Y model deformations of the monoidal category of coherent sheaves, thereby providing a concrete physical realization of deformation quantization for higher categorical structures. Overall, the RW boundary theory serves as a bridge between 3d topological field theory and modern categorified geometry, with potential applications to 3d mirror symmetry and quantum deformation theories in algebraic geometry.
Abstract
We study boundary conditions and defects in a three-dimensional topological sigma-model with a complex symplectic target space X (the Rozansky-Witten model). We show that boundary conditions correspond to complex Lagrangian submanifolds in X equipped with complex fibrations. The set of boundary conditions has the structure of a 2-category; morphisms in this 2-category are interpreted physically as one-dimensional defect lines separating parts of the boundary with different boundary conditions. This 2-category is a categorification of the Z/2-graded derived category of X; it is also related to categories of matrix factorizations and a categorification of deformation quantization (quantization of symmetric monoidal categories). In the appendix we describe a deformation of the B-model and the associated category of branes by forms of arbitrary even degree.
