Title Intermittency, metastability and coarse graining for coupled deterministic-stochastic lattice systems
Authors M.A. Katsoulakis, A.J. Majda, Alexandros Sopasakis
Alternative Location http://dx.doi.org/10.1088/0..., Restricted Access
Publication Nonlinearity
Year 2006
Volume 19
Issue 5
Pages 1021 - 1047
Document type Article
Status Published
Quality controlled Yes
Language eng
Publisher London Mathematical Society / IOP Science
Abstract English We study the role of strong particle/particle interactions and stochastic fluctuations<br> emanating from the micro-/sub-grid scale, in the context of a simple prototype hybrid system con-<br> sisting of a scalar linear ordinary differential equation (ODE), coupled to a microscopic spin flip<br> Ising lattice system. Due to the presence of strong interactions in the lattice model, the mean-field<br> approximation of this system is a Fitzhugh-Nagumo-type system of ODEs. However, microscopic<br> noise and local interactions will significantly alter the deterministic and spatially homogeneous<br> mean-field Fitzhugh-Nagumo behaviours (excitable, bistable and oscillatory) and will yield cor-<br> responding regimes with phenomena driven by the interaction of nonlinearity and noise across<br> scales, such as strong intermittency, metastability and random oscillations. Motivated by these<br> observations we consider a class of stochastic numerical approximations based on systematic<br> coarse-grainings of stochastic lattice dynamics. The resulting stochastic closures give rise to com-<br> putationally inexpensive reduced hybrid models that capture correctly the transient and long-time<br> behaviour of the full system; this is demonstrated by detailed time series analysis that includes<br> comparisons of power spectra and auto- and cross-correlations in time and space, especially in<br> examples dominated by strong interactions between scales and fluctuations, such as nucleation,<br> intermittent and random oscillation regimes.
ISBN/ISSN/Other ISSN: 1361-6544 (online)

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