Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
1994-08-02
Phys.Rev. D51 (1995) 4419-4444
Physics
High Energy Physics
High Energy Physics - Phenomenology
57 pages, 41 figures available upon request by mail, LATEX, PITT-94-07
Scientific paper
10.1103/PhysRevD.51.4419
The non-equilibrium dynamics of the first stage of the reheating process, that is dissipation via particle production is studied in scalar field theories in the unbroken and in the broken symmetry phase. We begin with a perturbative study to one loop and show explicitly that the mechanism of dissipation via particle production cannot be explained with a simple derivative term in the equation of motion. The dissipative contribution is non-local and there does not exist a local (Markovian) limit at zero temperature. Furthermore, we show that both an amplitude as well as a one-loop calculation present instabilities, requiring a non-perturbative resummation. Within the same approximations, we study an O(2) linear sigma model that allows to study dissipation by Goldstone bosons. We find infrared divergences that require non-perturbative resummation in order to understand the long-time dynamics. We obtain a perturbative Langevin equation that exhibits a generalized fluctuation-dissipation relation, with non-Markovian kernels and colored noise. We then study a Hartree approximation and clearly exhibit dissipative effects related to the thresholds to particle production. The asymptotic dynamics depends on the coupling and initial conditions but does not seem to lead to exponential relaxation. The effect of dissipation by Goldstone bosons is studied non-perturbatively in the large N limit in an O(N) theory. Dissipation produced by Goldstone bosons dramatically changes the picture of the phase transition. We find the remarkable result that for ``slow-roll'' initial conditions (with the expectation value of the field initially near the origin) the final value of the expectation value of the scalar field is very close to its initial value. We find that the minima of the effective action depend on the initial conditions. We provide extensive numerical analysis of the dynamics.
Boyanovsky Daniel
de Vega Hector J.
Holman Richard
S-Lee D.
Singh Amit
No associations
LandOfFree
Dissipation via Particle Production in Scalar Field Theories does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dissipation via Particle Production in Scalar Field Theories, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dissipation via Particle Production in Scalar Field Theories will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-228446