Abstract.
Long-range forces in the early universe may lead to early structure formation and, perhaps, they provide seeds for primordial black holes. In this talk, I am focusing on generalised Yukawa interactions, where a scalar field is coupled with a dark fermion in a general background cosmology. In the homogeneous limit we find scaling solutions where the scalar and fermion track each other energy density regardless of the background. Our study provides the first step for the study of pertubations.
(The slides are be available here)