Scalar normal modes of higher-dimensional gravitating kinks

The scalar normal modes of higher-dimensional gravitating kink solutions are derived. By perturbing to second order the gravity and matter parts of the action in the background of a five-dimensional kink, the effective Lagrangian of the scalar fluctuations is derived and diagonalized in terms of a single degree of freedom which is invariant under infinitesimal diffeomorphisms. The spectrum of the normal modes is discussed and applied to the analysis of short distance corrections to Newtonʹs law.