Perturbative description of dissipation in nonequilibrium field theory
- Department of Physics, The University, Leeds LS2 9JT, England (GB)
Dissipative effects, such as the relaxation of quasiparticle occupation numbers, arise from absorptive parts of Green's functions, which typically appear first at the second order of perturbation theory. Within the closed-time-path formalism, it is shown, using a generalized renormalization technique, that these absorptive parts may be approximately resummed so as to appear in unperturbed propagators. In this way, it becomes possible to study, in low-order perturbation theory, the evolution in time of a field theory which is driven away from thermal equilibrium by the presence in its Hamiltonian of explicitly time-dependent parameters. Particular attention is given to a scalar field with time-dependent mass, which is relevant to the dynamics of phase transitions in the very early Universe. Under favorable conditions, the analysis leads to a kinetic equation of the Boltzmann type, and an approximate numerical solution of this equation is presented for illustrative purposes.
- OSTI ID:
- 5149134
- Journal Information:
- Physical Review (Section) D: Particles and Fields; (USA), Vol. 40:10; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FIELD THEORIES
PERTURBATION THEORY
BOLTZMANN EQUATION
GREEN FUNCTION
HAMILTONIANS
MASS
PHASE TRANSFORMATIONS
PROPAGATOR
QUASI PARTICLES
RELAXATION
RENORMALIZATION
SCALAR FIELDS
SYMMETRY BREAKING
THERMAL EQUILIBRIUM
TIME DEPENDENCE
UNIVERSE
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUILIBRIUM
FUNCTIONS
MATHEMATICAL OPERATORS
PARTIAL DIFFERENTIAL EQUATIONS
QUANTUM OPERATORS
645400* - High Energy Physics- Field Theory