Nonperturbative evaluation of the diffusion rate in field theory at high temperatures

Journal Article · Thu Apr 15 04:00:00 EDT 1993 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.47.3476· OSTI ID:6710331

Bochkarev, A ^[1]; de Forcrand, P ^[2]

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1. Institut fuer Theoretische Physik, Universitaet Bern, CH-3012 Bern (Switzerland)
2. IPS, Eidgenoessische Technische Hochschule Zurich, Ch-8092 Zurich (Switzerland)

The Kramers approach to the rate of thermally activated escape from a metastable state is extended to field theory. The diffusion rate in the (1+1)-dimensional sine-Gordon model as a function of temperature and friction coefficient is evaluated numerically by solving the Langevin equation in real time. A clear crossover from the semiclassical to the high-temperature domain is observed. The temperature behavior of the diffusion rate allows one to determine the kink mass which is found equal to the corresponding classical value. Kramers predictions for the dependence on viscosity are qualitatively valid in this multidimensional case. In the limit of vanishing friction the diffusion rate is shown to coincide with the one obtained from direct measurements of the conventional classical real-time Green's function at finite temperature.

• OSTI ID: 6710331
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 47:8; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

662110* -- General Theory of Particles & Fields-- Theory of Fields & Strings-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DIFFUSION
ENERGY LEVELS
EQUATIONS
EXCITED STATES
FIELD EQUATIONS
FIELD THEORIES
FRICTION
FUNCTIONS
GREEN FUNCTION
LANGEVIN EQUATION
LIMITING VALUES
METASTABLE STATES
QUANTUM FIELD THEORY
SINE-GORDON EQUATION
TWO-DIMENSIONAL CALCULATIONS
VISCOSITY