Relaxation and kinetics in scalar field theories
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
- Department of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)
A new approach to the dynamics of relaxation and kinetics of thermalization in a scalar field theory is presented that incorporates the relevant time scales through the resummation of hard thermal loops. An alternative derivation of the kinetic equations for the {open_quote}{open_quote}quasiparticle{close_quote}{close_quote} distribution functions is obtained that allows a clear understanding of the different {open_quote}{open_quote}coarse-graining{close_quote}{close_quote} approximations usually involved in a kinetic description. This method leads to a systematic perturbative expansion to obtain the kinetic equations including hard thermal loop resummation and to an improvement including renormalization, off-shell effects, and contributions that change chemical equilibrium on short time scales. As a by-product of these methods we establish the equivalence between the relaxation time scale in the linearized equation of motion of the quasiparticles and the thermalization time scale of the quasiparticle distribution function in the {open_quote}{open_quote}relaxation time approximation{close_quote}{close_quote} including hard thermal loop effects. Hard thermal loop resummation dramatically modifies the scattering rate for long wavelength modes as compared to the usual (semi)classical estimate. Relaxation and kinetics are studied both in the unbroken and broken symmetry phases of the theory. The broken symmetry phase also provides the setting to obtain the contribution to the kinetic equations from processes that involve decay of a heavy scalar into light scalar particles in the medium. {copyright} {ital 1996 The American Physical Society.}
- Research Organization:
- Univ. of North Carolina, Chapel Hill, NC (United States)
- DOE Contract Number:
- FG05-85ER40219
- OSTI ID:
- 383430
- Journal Information:
- Physical Review, D, Vol. 54, Issue 6; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quantum kinetics and thermalization in an exactly solvable model
Real-time relaxation and kinetics in hot scalar QED: Landau damping