Dissipation via particle production in scalar field theories

Journal Article · Sat Apr 15 04:00:00 EDT 1995 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.51.4419· OSTI ID:26143

Boyanovsky, D; de Vega, H J; Holman, R; Lee, D; Singh, A ^[1]

---

1. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

We study the nonequilibrium evolution of the expectation value of a scalar field in the broken and unbroken symmetry cases. We find that the particles produced by parametric amplification give rise to dissipative behavior for this mode. However, a {Gamma} {center_dot}{phi} type of term {ital cannot} account for the dissipational dynamics. We are able to show clearly that perturbation theory breaks down at late times, so that dissipation in field theories can only be understood nonperturbatively. When Goldstone bosons are present we find infrared divergences that require a nonperturbative resummation to describe the long-time dynamics. We use the Hartree factorization and the large {ital N} approximation to the O({ital N}) linear {sigma} model to numerically as well as analytically understand the long-time behavior of the zero mode as well as that of the produced particles. The O({ital N}) model case is extremely interesting since, in the spontaneously broken case, the radial mode dissipates all of its energy into production of long-wavelength Goldstone modes. The minima of the effective action (determined by the final value of the expectation value of the scalar field) depend on the initial conditions.

• Research Organization: Carnegie-Mellon University
• DOE Contract Number: FG02-91ER40682
• OSTI ID: 26143
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 8 Vol. 51; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACTION INTEGRAL
DISSIPATION FACTOR
EXPECTATION VALUE
FACTORIZATION
FIELD THEORIES
GOLDSTONE BOSONS
INFRARED DIVERGENCES
O GROUPS
PARTICLE PRODUCTION
PERTURBATION THEORY
SCALAR FIELDS
SIGMA MODEL
SYMMETRY BREAKING
WAVELENGTHS