Universe reheating after inflation

Journal Article · Mon May 15 04:00:00 EDT 1995 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.51.5438· OSTI ID:57917

Shtanov, Y ^[1]; Traschen, J ^[2]; Brandenberger, R ^[3]

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1. Bogolyubov Institute for Theoretical Physics, Kiev 252143 (Ukraine)
2. Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
3. Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)

We study the problem of scalar particle production after inflation by an inflaton field which is oscillating rapidly relative to the expansion of the universe. We use the framework of the chaotic inflation scenario with quartic and quadratic inflaton potentials. Particles produced are described by a quantum scalar field {chi}, which is coupled to the inflaton via linear and quadratic couplings. The particle production effect is studied using the standard technique of Bogolyubov transformations. Particular attention is paid to parametric resonance phenomena which take place in the presence of the quickly oscillating inflaton field. We have found that in the region of applicability of perturbation theory the effects of parametric resonance are crucial, and estimates based on first-order Born approximation often underestimate the particle production. In the case of the quartic inflaton potential {ital V}({ital cphi})={lambda}{ital cphi}{sup 4}, the particle production process is very efficient for either type of coupling between the inflaton field and the scalar field {chi} even for small values of coupling constants. The energy density of the universe after the decay of the inflaton oscillations is in this case a factor [{lambda} ln(1/{lambda})]{sup {minus}1} times larger than the corresponding estimates based on first-order Born approximation. In the case of the quadratic inflaton potential the reheating process depends crucially on the type of coupling between the inflaton and the scalar field {chi} and on the magnitudes of the coupling constants. If the inflaton coupling to fermions and its linear (in inflaton field) coupling to scalar fields are suppressed, then, as previously discussed by Kofman, Linde, and Starobinsky, the inflaton field will eventually decouple from the rest of the matter, and the residual inflaton oscillations may provide the (cold) dark matter of the universe.

• Research Organization: Brown University
• DOE Contract Number: FG02-91ER40688
• OSTI ID: 57917
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 10 Vol. 51; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOGOLYUBOV TRANSFORMATION
BORN APPROXIMATION
COUPLING CONSTANTS
ENERGY DENSITY
INFLATION
INFLATIONARY UNIVERSE
OSCILLATIONS
PARTICLE PRODUCTION
POTENTIALS
SCALAR FIELDS