Browsing Statistical Physics by Author "Pagnini, G."
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Anomalous diffusion originated by two Markovian hoppingtrap mechanisms
Vitali, S.; Paradisi, P.; Pagnini, G. (2022)We show through intensive simulations that the paradigmatic features of anomalous diffusion are indeed the features of a (continuoustime) random walk driven by two different Markovian hoppingtrap mechanisms. If $p ... 
Centreofmass like superposition of OrnsteinUhlenbeck processes: A pathway to nonautonomous stochastic differential equations and to fractional diffusion
D’Ovidio, M.; Vitali, S.; Sposini, V.; Sliusarenko, O.; Paradisi, P.; Castellani, G.; Pagnini, G. (20181025)We consider an ensemble of Ornstein–Uhlenbeck processes featuring a population of relaxation times and a population of noise amplitudes that characterize the heterogeneity of the ensemble. We show that the centreofmass ... 
Concurent multiscale physical parametrization of firespotting: A study on the role of macro and mesoscale characteristics of the system
Egorova, V.; Trucchia, A.; Pagnini, G. (2018)The strong impact of wildfires in terms of lives and homes lost and of damage to ecosystems, calls for an urgent improvement in the risk management. The aim of the present research is the improvement of these software ... 
Crossover from anomalous to normal diffusion: truncated powerlaw noise correlations and applications to dynamics in lipid bilayers
MolinaGarcia, D.; Sandev, T.; Safdari, H.; Pagnini, G.; Chechkin, A.V.; Metzler, R. (20181018)The emerging diffusive dynamics in many complex systems shows a characteristic crossover behaviour from anomalous to normal diffusion which is otherwise fitted by two independent powerlaws. A prominent example for a ... 
DarrieusLandau instabilities in the framework of the Gequation
Pagnini, G.; Trucchia, A. (201704)We consider a model formulation of the flame front propagation in turbulent premixed combustion based on stochastic fluctuations imposed to the mean flame position. In particular, the mean flame motion is described by ... 
Discretizations of the spectral fractional Laplacian on general domains with Dirichlet, Neumann, and Robin boundary conditions
Cusimano, N.; Del Teso, F.; GerardoGiorda, L.; Pagnini, G. (20170428)In this work, we propose novel discretisations of the spectral fractional Laplacian on bounded domains based on the integral formulation of the operator via the heatsemigroup formalism. Specifically, we combine suitable ... 
Effective selfsimilar expansion for the GrossPitaevskii equation
Modugno, M.; Pagnini, G.; ValleBasagoiti, M.A. (201804)We consider an effective scaling approach for the free expansion of a onedimensional quantum wave packet, consisting in a selfsimilar evolution to be satisfied on average, i.e., by integrating over the coordinates. A ... 
Exact calculation of the mean firstpassage time of continuoustime random walks by nonhomogeneous WienerHopf integral equations
Dahlenburg, M.; Pagnini, G. (20221223)We study the mean firstpassage time (MFPT) for asymmetric continuoustime random walks in continuousspace characterised by waitingtimes with finite mean and by jumpsizes with both finite mean and finite variance. In ... 
Finiteenergy Lévytype motion through heterogeneous ensemble of Brownian particles
Sliusarenko, O.; Vitali, S.; Sposini, V.; Paradisi, P.; Chechkin, A.V.; Castellani, G.; Pagnini, G. (20190201)Complex systems are known to display anomalous diffusion, whose signature is a space/time scaling $x \sim t^\delta$ with $\delta \neq 1/2$ in the probability density function (PDF). Anomalous diffusion can emerge jointly ... 
Firespotting generated fires. Part I: The role of atmospheric stability
Egorova, V.; Trucchia, A.; Pagnini, G. (201902)This is the first part of two papers concerning firespotting generated fires. In this part we deal with the impact of macroscale factors, such as the atmospheric stability, and in the second part we deal with mesoscale ... 
Firespotting generated fires. Part II: The role of flame geometry and slope
Egorova, V.; Trucchia, A.; Pagnini, G. (2022)This is the second part of a series of two papers concerning firespotting generated fires. While, in the first part, we focus on the impact of macroscale factors on the growth of the burning area by considering the ... 
Firespotting modelling in operational wildfire simulators based on cellular automata: a comparison study
LópezDeCastro, M; Trucchia, A.; Morra di Cella, U; Fiorucci, P; Cardillo, A; Pagnini, G. (20230731)One crucial mechanism in the spread of wildfires is the socalled firespotting: a random phenomenon which occurs when embers are transported over large distances. Firespotting speeds up the Rate of Spread and starts new ... 
Firespotting modelling in operational wildfire simulators based on cellular automata: a comparison study.
LópezDeCastro, M; Trucchia, A.; Morra di Cella, U; Fiorucci, P; Cardillo, A; Pagnini, G. (2021)One crucial mechanism in the spread of wildfires is the socalled firespotting: a random phenomenon which occurs when embers are transported over large distances. Firespotting speeds up the Rate of Spread and starts ... 
The FokkerPlanck equation of the superstatistical fractional Brownian motion with application to passive tracers inside cytoplasm.
Runfola, C.; Vitali, S.; Pagnini, G. (2022)By collecting from literature data the experimental evidences of anomalous diffusion of passive tracers inside cytoplasm, and in particular of subdiffusion of mRNA molecules inside live E. coli cells, we get the probability ... 
The Fokker–Planck equation of the superstatistical fractional Brownian motion with application to passive tracers inside cytoplasm
Runfola, C.; Vitali, S.; Pagnini, G. (2022)By collecting from literature data experimental evidence of anomalous diffusion of passive tracers inside cytoplasm, and in particular of subdiffusion of mRNA molecules inside live Escherichia coli cells, we obtain the ... 
Fractional Brownian motion in a finite interval: correlations effect depletion or accretion zones of particles near boundaries
Guggenberger, T.; Pagnini, G.; Vojta, T.; Metzler, R. (201902)Fractional Brownian motion (FBM) is a Gaussian stochastic process with stationary, longtime correlated increments and is frequently used to model anomalous diffusion processes. We study numerically FBM confined to a finite ... 
Fractional Diffusion and Medium Heterogeneity: The Case of the Continuos Time Random Walk
Sposini, V.; Vitali, S.; Paradisi, P.; Pagnini, G. (20210724)In this contribution we show that fractional diffusion emerges from a simple Markovian Gaussian random walk when the medium displays a powerlaw heterogeneity. Within the framework of the continuous time random walk, the ... 
Fractional kinetics emerging from ergodicity breaking in random media
MolinaGarcia, D.; Minh Pham, T.; Paradisi, P.; Manzo, C.; Pagnini, G. (2016)We present a modelling approach for diffusion in a complex medium characterized by a random lengthscale. The resulting stochastic process shows subdiffusion with a behavior in qualitative agreement with single particle ... 
Fractional kinetics in random/complex media
Pagnini, G. (2019)In this chapter, we consider a randomlyscaled Gaussian process and discuss a number of applications to model fractional diffusion. Actually, this approach can be understood as a Gaussian diffusion in a medium characterized ... 
Fractional relaxation with timevarying coefficient
Garra, R.; Giusti, A.; Mainardi, F.; Pagnini, G. (20141231)From the point of view of the general theory of the hyperBessel operators, we consider a particular operator that is suitable to generalize the standard process of relaxation by taking into account both memory effects of ...