On the reduction of 4d N=1 theories on S^2
Abhijit Gadde, Shlomo S. Razamat, Brian Willett
TL;DR
The paper analyzes how 4d N=1 theories compactified on S^2 yield 2d N=(0,2) theories, identifying a necessary condition—non-negative integer U(1)_R charges—for the infrared and small-S^2 limits to commute. It develops a concrete reduction rule mapping 4d chiral multiplets to 2d N=(0,2) multiplets, and leverages the S^2 × T^2 index and the elliptic genus to test and constrain the resulting theories. Through detailed examinations of Seiberg dualities and their 2d reductions, it demonstrates that 4d dualities imply corresponding 2d dualities, including (0,2), (2,2), and (0,4) cases, depending on R-symmetry choices. The work further extends to N=2 models, revealing a spectrum of 2d theories with enhanced supersymmetry and providing multiple consistency checks via elliptic genera. Overall, the approach offers a unified, partition-function–driven framework to derive and verify 2d dualities from higher-dimensional dualities.
Abstract
We discuss reductions of general N=1 four dimensional gauge theories on S^2. The effective two dimensional theory one obtains depends on the details of the coupling of the theory to background fields, which can be translated to a choice of R-symmetry. We argue that, for special choices of R-symmetry, the resulting two dimensional theory has a natural interpretation as an N=(0,2) gauge theory. As an application of our general observations, we discuss reductions of N=1 and N=2 dualities and argue that they imply certain two dimensional dualities.
