Primordial dark matter from curvature induced symmetry breaking

We demonstrate that adiabatic dark matter can be generated by gravity induced symmetry breaking during inflation. We study a Z(2) symmetric scalar singlet that couples to other fields only through gravity and for which the symmetry is broken by the space-time curvature during inflation when the non-minimal coupling xi is negative. We find that the symmetry breaking leads to the formation of adiabatic dark matter with the observed abundance for the singlet mass m similar to MeV and vertical bar xi vertical bar similar to 1.