Contributor info: Dr Eduardo Garcia Valdecasas

Daniel Aloni, Eduardo García-Valdecasas, Matthew Reece, Motoo Suzuki

SciPost Phys. 17, 031 (2024) · published 1 August 2024 | Toggle abstract · pdf

Spontaneous breaking of symmetries leads to universal phenomena. We extend this notion to $(-1)$-form U(1) symmetries. The spontaneous breaking is diagnosed by a dependence of the vacuum energy on a constant background field $\theta$, which can be probed by the topological susceptibility. This leads to a reinterpretation of the Strong CP problem as arising from a spontaneously broken instantonic symmetry in QCD. We discuss how known solutions to the problem are unified in this framework and explore some, so far unsuccessful, attempts to find new solutions.

Jeremias Aguilera Damia, Riccardo Argurio, Eduardo Garcia-Valdecasas

SciPost Phys. 14, 067 (2023) · published 12 April 2023 | Toggle abstract · pdf

We show that very simple theories of abelian gauge fields with a cubic Chern-Simons term in 5d have an infinite number of non-invertible codimension two defects. They arise by dressing the symmetry operators of the broken electric 1-form symmetry with a suitable topological field theory, for any rational angle. We further discuss the same theories in the presence of a 4d boundary, and more particularly in a holographic setting. There we find that the bulk defects, when pushed to the boundary, have various different fates. Most notably, they can become codimension one non-invertible defects of a boundary theory with an ABJ anomaly.