  We examine an example of spontaneous symmetry breaking in a double-well
waveguide with a symmetric potential. The ground state of the system beyond a
critical power becomes asymmetric. The effect is illustrated numerically, and
quantitatively analyzed via a Galerkin truncation that clearly shows the
bifurcation from a symmetric to an asymmetric steady state. This phenomenon is
also demonstrated experimentally when a probe beam is launched appropriately
into an optically induced photonic lattice in a photorefractive material.
