Nonequilibrium inflaton dynamics and reheating: Back reaction of parametric particle creation and curved spacetime effects
Abstract
We present a detailed and systematic analysis of the nonperturbative, nonequilibrium dynamics of a quantum field in the reheating phase of inflationary cosmology, including full back reactions of the quantum field on the curved spacetime, as well as the fluctuations on the mean field. We use the O(N) field theory with unbroken symmetry in a spatially flat FriedmannRobertsonWalker (FRW) universe to study the dynamics of the inflaton in the postinflation, preheating stage. Oscillations of the inflaton{close_quote}s zero mode induce parametric amplification of quantum fluctuations, resulting in a rapid transfer of energy to the inhomogeneous modes of the inflaton field. The largeamplitude oscillations of the mean field, as well as stimulated emission effects require a nonperturbative formulation of the quantum dynamics, while the nonequilibrium evolution requires a statistical field theory treatment. We adopt the coupled nonperturbative equations for the mean field and variance derived in a preceding paper [S. A. Ramsey and B. L. Hu, this issue, Phys. Rev. D {bold 56}, 661 (1997)] by means of a twoparticleirreducible (2PI), closedtimepath (CTP) effective action for curved spacetimes while specialized to a dynamical FRW background, up to leading order in the 1/N expansion. Adiabatic regularization is employed to yield a covariantly conserved,more »
 Authors:

 Department of Physics, University of Maryland, College Park, Maryland 207424111 (United States)
 Publication Date:
 OSTI Identifier:
 527071
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review, D
 Additional Journal Information:
 Journal Volume: 56; Journal Issue: 2; Other Information: PBD: Jul 1997
 Country of Publication:
 United States
 Language:
 English
 Subject:
 66 PHYSICS; INFLATIONARY UNIVERSE; DYNAMICS; COSMOLOGY; AXIOMATIC FIELD THEORY; PARTICLE PRODUCTION; FLUCTUATIONS; O GROUPS; QUANTUM FIELD THEORY; OSCILLATIONS; MEANFIELD THEORY; ENERGYMOMENTUM TENSOR; SPACETIME
Citation Formats
Ramsey, S A, and Hu, B L. Nonequilibrium inflaton dynamics and reheating: Back reaction of parametric particle creation and curved spacetime effects. United States: N. p., 1997.
Web. doi:10.1103/PhysRevD.56.678.
Ramsey, S A, & Hu, B L. Nonequilibrium inflaton dynamics and reheating: Back reaction of parametric particle creation and curved spacetime effects. United States. doi:10.1103/PhysRevD.56.678.
Ramsey, S A, and Hu, B L. Tue .
"Nonequilibrium inflaton dynamics and reheating: Back reaction of parametric particle creation and curved spacetime effects". United States. doi:10.1103/PhysRevD.56.678.
@article{osti_527071,
title = {Nonequilibrium inflaton dynamics and reheating: Back reaction of parametric particle creation and curved spacetime effects},
author = {Ramsey, S A and Hu, B L},
abstractNote = {We present a detailed and systematic analysis of the nonperturbative, nonequilibrium dynamics of a quantum field in the reheating phase of inflationary cosmology, including full back reactions of the quantum field on the curved spacetime, as well as the fluctuations on the mean field. We use the O(N) field theory with unbroken symmetry in a spatially flat FriedmannRobertsonWalker (FRW) universe to study the dynamics of the inflaton in the postinflation, preheating stage. Oscillations of the inflaton{close_quote}s zero mode induce parametric amplification of quantum fluctuations, resulting in a rapid transfer of energy to the inhomogeneous modes of the inflaton field. The largeamplitude oscillations of the mean field, as well as stimulated emission effects require a nonperturbative formulation of the quantum dynamics, while the nonequilibrium evolution requires a statistical field theory treatment. We adopt the coupled nonperturbative equations for the mean field and variance derived in a preceding paper [S. A. Ramsey and B. L. Hu, this issue, Phys. Rev. D {bold 56}, 661 (1997)] by means of a twoparticleirreducible (2PI), closedtimepath (CTP) effective action for curved spacetimes while specialized to a dynamical FRW background, up to leading order in the 1/N expansion. Adiabatic regularization is employed to yield a covariantly conserved, renormalized energymomentum tensor. The renormalized dynamical equations are evolved numerically from initial data which are generic to the end state of slow roll in many inflationary cosmological scenarios. The initial conditions consist of a largeamplitude, quasiclassical, oscillating mean field {l_angle}{Phi}{r_angle} with variance {l_angle}{Phi}{sup 2}{r_angle}{minus}{l_angle}{Phi}{r_angle}{sup 2} around the de Sitterinvariant vacuum. (Abstract Truncated)},
doi = {10.1103/PhysRevD.56.678},
journal = {Physical Review, D},
number = 2,
volume = 56,
place = {United States},
year = {1997},
month = {7}
}