Nonperturbative quantum dynamics of a new inflation model
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
- LPTHE, Universite Pierre et Marie Curie (Paris VI) et Denis Diderot (Paris VII), Tour 16, 1er. etage, 4, Place Jussieu75252Paris, Cedex 05 (France)
We consider an O(N) model coupled self-consistently to gravity in the semiclassical approximation, where the field is subject to {open_quotes}new inflation{close_quotes} type initial conditions. We study the dynamics self-consistently and non-perturbatively with non-equilibrium field theory methods in the large N limit. We find that spinodal instabilities drive the growth of non-perturbatively large quantum fluctuations which shut off the inflationary growth of the scale factor. We find that a very specific combination of these large fluctuations plus the inflaton zero mode assemble into a new effective field. This new field behaves classically and it is the object which actually rolls down. We show how this reinterpretation saves the standard picture of how metric perturbations are generated during inflation and that the spinodal growth of fluctuations dominates the time dependence of the Bardeen variable for superhorizon modes during inflation. We compute the amplitude and index for the spectrum of scalar density and tensor perturbations and argue that in all models of this type the spinodal instabilities are responsible for a {open_quotes}red{close_quotes} spectrum of primordial scalar density perturbations. A criterion for the validity of these models is provided and contact with the reconstruction program is established validating some of the results within a non-perturbative framework. The decoherence aspects and the quantum to classical transition through inflation are studied in detail by following the full evolution of the density matrix and relating the classicality of cosmological perturbations to that of long-wavelength matter fluctuations. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 574024
- Journal Information:
- Physical Review, D, Vol. 57, Issue 4; Other Information: PBD: Feb 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quantum inflaton, primordial perturbations, and CMB fluctuations
Spinodal decomposition and inflation: Dynamics and metric perturbations