Cosmon inflation

The cosmon field responsible for dynamical dark energy can induce an inflationary period in early cosmology. Details depend on dilatation symmetry breaking terms in its potential and kinetic term that are relevant only during early stages of the evolution of the universe. For a large range of parameters we find realistic primordial density fluctuations. As a particular example we discuss a model with almost static geometry in the Jordan frame for all epochs of cosmology. Here the cosmic evolution of the Hubble parameter is replaced by a variation of the Planck mass and particle masses. This model predicts a spectral index n=0.97 and a ratio for tensor to scalar fluctuations r = 0.13. (C) 2013 Elsevier B.V. All rights reserved.