Dual Boundary Conditions in 3d SCFT's
Tudor Dimofte, Davide Gaiotto, Natalie M. Paquette
TL;DR
The paper develops a comprehensive framework for half-BPS boundary conditions in 3d ${\mathcal N}=2$ gauge theories, preserving ${\mathcal N}=(0,2)$ at the boundary and matching UV boundary data through IR dualities via duality interfaces. Central to the approach is the 3d half-index, extended to Dirichlet boundary conditions and boundary monopole sectors, which serves as a nonperturbative check of dualities across abelian and nonabelian theories, including Aharony duality, level-rank dualities, and particle-vortex triality. The authors systematically construct dual boundary conditions and interfaces for a large class of dual pairs (SQED/XYZ, SQCD/detYZ, level-rank pairs, Aharony dual pairs) and verify anomaly matching and half-index identities, often via explicit monopole-sum computations and boundary Fermi/chiral multiplet couplings. The results illuminate deep links between 3d boundary dynamics and 2d boundary CFTs (e.g., WZW and coset models), and outline a broad program to extend boundary dualities to more general SUSY settings and to non-supersymmetric dualities.
Abstract
We propose matching pairs of half-BPS boundary conditions related by IR dualities of 3d $\mathcal{N}=2$ gauge theories. From these matching pairs we construct duality interfaces. We test our proposals by anomaly matching and the computation of supersymmetric indices. Examples include basic abelian dualities, level-rank dualities, and Aharony dualities.
