  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.
