3d Mirrors and Phase Diagrams of Abelian Gauge Theories

This paper presents new developments in the study of 3d mirror symmetry and the phase structure of Abelian gauge theories. Previous works identified 3d mirrors for a specific class of theories, termed ``simple" Abelian theories. This work extends this framework by proposing 3d mirrors for ``non-simple" Abelian theories with both discrete and continuous gauge group factors. The proposal is supported by evidence from an exact operator map between the Higgs/Coulomb branch of one theory and the Coulomb/Higgs branch of its 3d mirror. Further support is provided by explicit Hilbert series computations. An algorithm for computing the Hasse (phase) diagram of the Higgs branch of both simple and non-simple Abelian theories is introduced, uncovering a recently discovered family of isolated singularities among the elementary slices. A bottom-up algorithm for computing the Coulomb branch Hasse diagram of these theories is also introduced, and the two algorithms are tested against each other via 3d mirror symmetry.