Geometric back-reaction in pre-inflation from relativistic quantum   geometry
  The pre-inflationary evolution of the universe describes the beginning of the expansion from a static initial state, such that the Hubble parameter is initially zero, but increases to an asymptotic constant value, in which it could achieve a de Sitter (inflationary) expansion. The expansion is driven by a background phantom field. The back-reaction effects at this moment should describe vacuum geometrical excitations, which are studied with detail in this work using Relativistic Quantum Geometry. 
Marcos R. A. Arcod\'ia, Mauricio Bellini (IFIMAR - CONICET & UNMdP)
gr-qc hep-th