Triangle Seminars
Wednesday, 24 Jun 2026
From 3d QED to the multicritical point of the Fradkin-Shenker model
📍 London
Pierluigi Niro
(SISSA)
Abstract:
The Fradkin-Shenker model in 2+1 dimensions, which is equivalent to the toric code deformed by an in-plane magnetic field, is a paradigmatic example of Higgs-confinement continuity. Its phase diagram contains a multicritical point where mutually non-local electric and magnetic excitations, exchanged by a self-duality symmetry, become simultaneously massless. We propose a continuum QFT description of the multicritical point in terms of 3d QED with two charge-1 Dirac fermions and a charge-2 Higgs field with Yukawa couplings, deformed by monopole operators. We show that this theory reproduces all features of the Fradkin-Shenker phase diagram upon massive deformations. Finally, we conjecture a multicritical duality of the continuum theory with a suitable deformation of the easy-plane CP^1 model. This talk is based on arXiv:2602.23420 together with T. Dumitrescu and R. Thorngren.
The Fradkin-Shenker model in 2+1 dimensions, which is equivalent to the toric code deformed by an in-plane magnetic field, is a paradigmatic example of Higgs-confinement continuity. Its phase diagram contains a multicritical point where mutually non-local electric and magnetic excitations, exchanged by a self-duality symmetry, become simultaneously massless. We propose a continuum QFT description of the multicritical point in terms of 3d QED with two charge-1 Dirac fermions and a charge-2 Higgs field with Yukawa couplings, deformed by monopole operators. We show that this theory reproduces all features of the Fradkin-Shenker phase diagram upon massive deformations. Finally, we conjecture a multicritical duality of the continuum theory with a suitable deformation of the easy-plane CP^1 model. This talk is based on arXiv:2602.23420 together with T. Dumitrescu and R. Thorngren.
Posted by: Kiarash Naderi