  We consider an oblate Bose-Einstein condensate of heteronuclear polar
molecules in a weak applied electric field. This system supports a rich
quasiparticle spectrum that plays a critical role in determining its bulk
dielectric properties. In particular, in sufficiently weak fields the system
undergoes a polarization wave rotonization, leading to the development of
textured electronic structure and a dielectric instability that is
characteristic of the onset of a negative static dielectric function.
