Inflation from Broken Scale Invariance
Abstract
We construct a model of inflation based on a lowenergy effective theory of spontaneously broken global scale invariance. This provides a shift symmetry that protects the inflaton potential from quantum corrections. Since the underlying scale invariance is noncompact, arbitrarily large inflaton field displacements are readily allowed in the lowenergy effective theory. A weak breaking of scale invariance by almost marginal operators provides a nontrivial inflaton minimum, which sets and stabilizes the final lowenergy value of the Planck scale. The underlying scale invariance ensures that the slowroll approximation remains valid over large inflaton displacements, and yields a scale invariant spectrum of perturbations, as required by the cosmic microwave background observations.
 Publication:

Physical Review Letters
 Pub Date:
 October 2014
 DOI:
 10.1103/PhysRevLett.113.161302
 arXiv:
 arXiv:1406.5192
 Bibcode:
 2014PhRvL.113p1302C
 Keywords:

 98.80.Cq;
 11.30.Qc;
 Particletheory and fieldtheory models of the early Universe;
 Spontaneous and radiative symmetry breaking;
 High Energy Physics  Theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 18 pages, 3 figures