Erlangen 2026 – scientific programme

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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik

MP 8: Poster Session

MP 8.4: Poster

Wednesday, March 18, 2026, 18:00–18:45, Redoutensaal

Symmetry-breaking constraints from higher-group structure in axion electrodynamics — •Timo Schulze — II. Institut für Theoretische Physik, Universität Hamburg

Over the past decade, generalised symmetries have opened a new perspective on global symmetries by describing them in terms of higher categorical structures. In a d-dimensional QFT, a q-form symmetry is generated by topological defects supported on closed (d−q−1)-manifolds, acting on q-dimensional charged operators. In axion electrodynamics, electric and magnetic 1-form symmetries as well as axionic 0- and 2-form symmetries can combine into a higher-group structure. Building on previous work by Brennan and Cordova, we study and attempt to formalise how higher-group data constrain the order of emergence of these symmetries along RG flows. We suggest further constraints on explicit breaking terms for both electric and magnetic 1-form symmetries below the breaking scale of the axionic 0-form shift symmetry. In particular, this implies that magnetically charged probe particles below that scale must also be electrically charged.

Keywords: Generalised Symmetries; Higher-form symmetry; Higher-group symmetry; Symmetry breaking; Axion