SubPlanckian twofield inflation consistent with the Lyth bound
Abstract
The BICEP2 observation of a large tensortoscalar ratio, r = 0.20^{+0.07}_{0.05}, implies that the inflaton phi in singlefield inflation models must satisfy phi ~ 10M_{Pl} in order to produce sufficient inflation. This is a problem if interaction terms suppressed by the Planck scale impose a bound phi lesssim M_{Pl}. Here we consider whether it is possible to have successful subPlanckian inflation in the case of twofield inflation. The trajectory in field space cannot be radial if the effective singlefield inflaton is to satisfy the Lyth bound. By considering a complex field Φ, we show that a near circular but aperiodic modulation of a Φ^{4} potential can reproduce the results of phi^{2} chaotic inflation for n_{s} and r while satisfying Φ lesssim 0.01 M_{Pl} throughout. More generally, for models based on a Φ^{4} potential, the simplest subPlanckian models are equivalent to phi^{2} and phi^{4/3} chaotic inflation.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 September 2014
 DOI:
 10.1088/14757516/2014/09/027
 arXiv:
 arXiv:1404.4620
 Bibcode:
 2014JCAP...09..027M
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Theory
 EPrint:
 7 pages, 2 figures. Some additional references and discussion. Version published in JCAP