# Covert Symmetry Breaking

**Authors:** C. W. Erickson, A. D. Harrold, Rahim Leung, K. S. Stelle  
**arXiv:** [2007.12192](https://arxiv.org/abs/2007.12192)  
**Date:** 2020-07-23  
**Summary page:** https://www.summarizepaper.com/fr/paper/2007.12192v1/

## Abstract

Reduction from a higher-dimensional to a lower-dimensional field theory can display special features when the zero-level ground state has nontrivial dependence on the reduction coordinates. In particular, a delayed `covert' form of spontaneous symmetry breaking can occur, revealing itself only at fourth order in the lower-dimensional effective field theory action. This phenomenon is explored in a simple model of $(d+1)$-dimensional scalar QED with one dimension restricted to an interval with Dirichlet/Robin boundary conditions on opposing ends. This produces an effective $d$-dimensional theory with Maxwellian dynamics at the free theory level, but with unusual symmetry breaking appearing in the quartic vector-scalar interaction terms. This simple model is chosen to illuminate the mechanism of effects which are also noted in gravitational braneworld scenarios.