Origin of density fluctuations in extended inflation
Abstract
The density fluctuations (both curvature and isocurvature) that arise due to quantum fluctuations in a simple model of extended inflation based upon the JordanBransDicke theory are calculated. Curvature fluctuations arise due to quantum fluctuations in the BransDicke field, in general have a nonscaleinvariant spectrum, and can have an amplitude that is cosmologically acceptable and interesting without having to tune any coupling constant to a very small value. The density perturbations that arise due to the inflation field are subdominant. If there are other massless fields in the theory, e.g., an axion or an ilion, then isocurvature fluctuations arise in these fields too. Production of gravitational waves and the massless particles associated with excitations of the BransDicke field are also discussed. Several attempts at more realistic models of extended inflation are also analyzed. The importance of the Einstein conformal frame in calculating curvature fluctuations is emphasized. When viewed in this frame, extended inflation closely resembles slowrollover inflation with an exponential potential and the usual formula for the amplitude of curvature perturbations applies.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 May 1990
 Bibcode:
 1990STIN...9025915K
 Keywords:

 Astronomical Models;
 Cosmology;
 Curvature;
 Density Distribution;
 Perturbation;
 Variations;
 Broken Symmetry;
 Excitation;
 Gravitational Waves;
 Astrophysics