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Pedro Haerter

Publications and source records attributed to Pedro Haerter.

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Bayesian Basin Tracking: Efficient Global Continuation of Multistable Dynamical Systems

Mapping the global phase space of high-dimensional multistable dynamical systems is computationally prohibitive because conventional approaches require extensive numerical integration. Here, we introduce Bayesian Basin Tracking (BBT), an adaptive Bayesian framework that exploits the persistence of basin boundaries under parameter continuation to reconstruct global phase-space structure using only a fraction of the simulations required by conventional methods. By modeling the probability that a sampled initial condition converges to a particular attractor, the method represents the phase-space geometry established at a given parameter value through a Dirichlet-multinomial model. At a nearby parameter value, these probabilities are estimated by updating the prior distribution with newly sampled data. To detect boundary crises and bifurcations autonomously, we use the log Bayes factor as an information-theoretic sensor that triggers dense resampling only when structural changes render the historical prior statistically implausible. We validate the framework using the discrete H\'enon map, the continuous-time Duffing oscillator, and a 300-dimensional network of coupled R\"ossler oscillators. BBT overcomes the restrictive dimensional scaling of deterministic grid tessellations by concentrating the most computationally demanding calculations in structurally volatile regions. In high-dimensional synchronization landscapes, it achieves an almost sixfold computational speed-up while retaining theoretically derived error bounds.

nlin.CD

Synchronization of phase oscillators due to nonlocal coupling mediated by the slow diffusion of a substance

Many systems of physical and biological interest are characterized by assemblies of phase oscillators whose interaction is mediated by a diffusing chemical. The coupling effect results from the fact that the local concentration of the mediating chemical affects both its production and absorption by each oscillator. Since the chemical diffuses through the medium in which the oscillators are embedded, the coupling among oscillators is non-local: it considers all the oscillators depending on their relative spatial distances. We considered a mathematical model for this coupling, when the diffusion time is arbitrary with respect to the characteristic oscillator periods, yielding a system of coupled nonlinear integro-differential equations which can be solved using Green functions for appropriate boundary conditions. In this paper we show numerical solutions of these equations for three finite domains: a linear one-dimensional interval, a rectangular, and a circular region, with absorbing boundary conditions. From the numerical solutions we investigate phase and frequency synchronization of the oscillators, with respect to changes in the coupling parameters for the three considered geometries.

nlin.AO