  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.
