Primordial flat frame -- a new view on inflation

Understand

Models of inflationary cosmology admit a choice of the metric for which the geometry of homogeneous isotropic solutions becomes flat Minkowski space in the infinite past.

• In this primordial flat frame all mass scales vanish in the infinite past and quantum scale symmetry is realized.
• The cosmological evolution is dominantly described by the slow increase of a scalar field which sets the scale of all masses.
• We construct the primordial flat frame for standard models of inflation as Starobinsky inflation or chaotic inflation.