  We show that a Bose-Einstein condensate of heteronuclear molecules in the
regime of small and static electric fields is described by a quantum rotor
model for the macroscopic electric dipole moment of the molecular gas cloud. We
solve this model exactly and find the symmetric, i.e., rotationally invariant,
and dipolar phases expected from the single-molecule problem, but also an axial
and planar nematic phase due to many-body effects. Investigation of the
wavefunction of the macroscopic dipole moment also reveals squeezing of the
probability distribution for the angular momentum of the molecules.
