Biomedical subjects

F Ginelli

Publications and source records attributed to F Ginelli.

3 recordsLinked to original sources

PubMed2005

Directed percolation with long-range interactions: Modeling nonequilibrium wetting.

It is argued that some phase transitions observed in models of nonequilibrium wetting phenomena are related to contact processes with long-range interactions. This is investigated by introducing a model where the activation rate of a site at the edge of an inactive island of length l is 1+a l(-sigma) . Mean-field analysis and numerical simulations indicate that for sigma>1 the transition is continuous and belongs to the universality class of directed percolation, while for 0<sigma<1 , the transition becomes first order. This criterion is then applied to discuss critical properties of various models of nonequilibrium wetting.

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PubMed2003

From multiplicative noise to directed percolation in wetting transitions.

A simple one-dimensional microscopic model of the depinning transition of an interface from an attractive hard wall is introduced and investigated. Upon varying a control parameter, the critical behavior observed along the transition line changes from a directed-percolation type to a multiplicative-noise type. Numerical simulations allow for a quantitative study of the multicritical point separating the two regions. Mean-field arguments and the mapping on yet a simpler model provide some further insight on the overall scenario.

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PubMed2003

Relationship between directed percolation and the synchronization transition in spatially extended systems.

We study the nature of the synchronization transition in spatially extended systems by discussing a simple stochastic model. An analytic argument is put forward showing that, in the limit of discontinuous processes, the transition belongs to the directed percolation (DP) universality class. The analysis is complemented by a detailed investigation of the dependence of the first passage time for the amplitude of the difference field on the adopted threshold. We find the existence of a critical threshold separating the regime controlled by linear mechanisms from that controlled by collective phenomena. As a result of this analysis, we conclude that the synchronization transition belongs to the DP class also in continuous models. The conclusions are supported by numerical checks on coupled map lattices too.

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