Gravitational waves in warped compactifications
  We study gravitational waves propagating on a warped Minkowski space-time
with D-4 compact extra dimensions. While Kaluza-Klein scales are typically too
high for any current detection, we analyse how the warp factor changes the
Kaluza-Klein spectrum of gravitational waves. To that end we provide a complete
and explicit expression for the warp factor, as well as the Green's function,
on a d-dimensional torus. This expression differs from that of braneworld
models and should find further uses in string compactifications. We then
evaluate the Kaluza-Klein spectrum of gravitational waves. Our preliminary
numerical results indicate not only a deviation from the standard toroidal
spectrum, but also that the first masses get lowered due to the warp factor.
