16 research outputs found
Parametric Resonance in an Expanding Universe
Parametric resonance has been discussed as a mechanism for copious particle
production following inflation. Here we present a simple and intuitive
calculational method for estimating the efficiency of parametric amplification
as a function of parameters. This is important for determining whether resonant
amplification plays an important role in the reheating process. We find that
significant amplification occurs only for a limited range of couplings and
interactions.Comment: 18 pages, Latex, 4 figure
Topologically nontrivial time-dependent chiral condensates
Topologically nontrivial time-dependent solutions of the classical nonlinear
sigma model are studied as candidates of the disoriented chiral condensate
(DCC) in 3+1 dimensions. Unlike the analytic solutions so far discussed, these
solutions cannot be transformed into isospin-uniform ones by chiral rotations.
If they are produced as DCC's, they can be detected by a distinct pattern in
the angle-rapidity distribution of the neutral-to-chrged-pion ratio.Comment: 11 pages, 3 figures available upon request to autho