Search Results - subject:"Field theory"

Coupling theory for counterion distributions based in Tsallis statistics

Garcı́a-Morales, V; Cervera, J; Pellicer, J - In: Physica A: Statistical Mechanics and its Applications 339 (2004) 3, pp. 482-490

It is well known that the Poisson–Boltzmann (PB) equation yields the exact counterion density around charged objects in the weak coupling limit. In this paper, we generalize the PB approach to account for coupling of arbitrary strength by making use of Tsallis q-exponential distributions. Both...

Persistent link: https://www.econbiz.de/10011061691

On singular probability densities generated by extremal dynamics

Garcia, Guilherme J.M.; Dickman, Ronald - In: Physica A: Statistical Mechanics and its Applications 332 (2004) C, pp. 318-336

several variants via mean-field theory and simulation. In all cases, we find that p(x) is singular at one or more points, as a … updating rule: we find the same value for the exponent π for all variants. Mean-field theory, which furnishes an exact … the modified processes mean-field theory takes the form of a functional equation for p(x). …

Persistent link: https://www.econbiz.de/10011062623

Generalized thermostatistics and mean-field theory

Naudts, Jan - In: Physica A: Statistical Mechanics and its Applications 332 (2004) C, pp. 279-300

The present paper studies a large class of temperature-dependent probability distributions and shows that entropy and energy can be defined in such a way that these probability distributions are the equilibrium states of a generalized thermostatistics, which is obtained from the standard...

Persistent link: https://www.econbiz.de/10010588438

Quasi-stationary distributions for models of heterogeneous catalysis

Oliveira, Marcelo M. de; Dickman, Ronald - In: Physica A: Statistical Mechanics and its Applications 343 (2004) C, pp. 525-542

improved, consistent one-site mean-field theory for the ZGB model. …

Persistent link: https://www.econbiz.de/10010590511

ANALYSIS AND MODELING OF SCIENCE COLLABORATION NETWORKS

PÜTSCH, FELIX - In: Advances in Complex Systems (ACS) 06 (2003) 04, pp. 477-485

We analyze a science collaboration network, i.e. a network whose nodes are scientists with edges connecting them for each paper published together. Furthermore, we develop a model for the simulation of discontiguous small-world networks that shows good coherence with empirical data.

Persistent link: https://www.econbiz.de/10004977712

A note on the Markov property of stochastic processes described by nonlinear Fokker–Planck equations

Frank, T.D. - In: Physica A: Statistical Mechanics and its Applications 320 (2003) C, pp. 204-210

We study the Markov property of processes described by generalized Fokker–Planck equations that are nonlinear with respect to probability densities such as mean field Fokker–Planck equations and Fokker–Planck equations related to generalized thermostatistics. We show that their transient...

Persistent link: https://www.econbiz.de/10010872945

Surface magnetism: phase transitions in quantum and classical models

Cabral Neto, J.; Sousa, J. Ricardo de - In: Physica A: Statistical Mechanics and its Applications 319 (2003) C, pp. 319-330

classical O(n) models. We use correlated effective field theory. The multicritical point Δc and the crossover exponent φ are …

Persistent link: https://www.econbiz.de/10011058042

Onsager's regression and the field theory of parabolic transport processes

Gambár, Katalin; Márkus, Ferenc - In: Physica A: Statistical Mechanics and its Applications 320 (2003) C, pp. 193-203

On the basis of a Hamiltonian and canonical formalism of simple parabolic transport processes the action for short time intervals can be calculated. In the knowledge of action, we can examine the stochastic behavior of these processes and we conclude that these are Markovian in the space of...

Persistent link: https://www.econbiz.de/10011059086

Gauge symmetry in Fokker–Planck dynamics

de Montigny, M.; Khanna, F.C.; Santana, A.E. - In: Physica A: Statistical Mechanics and its Applications 323 (2003) C, pp. 327-335

Using a Galilean metric approach, based on an embedding of the Euclidean space into a (4+1)-Minkowski space, we analyze a gauge invariant Lagrangian associated with a Riemannian manifold R, with metric g. With a specific choice of the gauge condition, the Euler–Lagrange equations are written...

Persistent link: https://www.econbiz.de/10010589367

Thermodynamic potentials for the infinite range Ising model with strong coupling

Hilfer, R. - In: Physica A: Statistical Mechanics and its Applications 320 (2003) C, pp. 429-434

The specific Gibbs free energy has been calculated for the infinite range Ising model with fixed and finite interaction strength. The model shows a temperature driven first-order phase transition that differs from the infinite ranged Ising model with weak coupling. In the temperature-field phase...

Persistent link: https://www.econbiz.de/10010591513