Statistical Physics
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Fractional Diffusion and Medium Heterogeneity: The Case of the Continuos Time Random Walk
(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 ... 
Stochastic Properties of Colliding Hard Spheres in a Nonequilibrium Thermal Bath
(20210724)We consider the problem of describing the dynamics of a test particle moving in a thermal bath using the stochastic differential equations. We briefly recall the stochastic approach to the Brownian based on the statistical ... 
Stochastic resetting by a random amplitude
(20210518)Stochastic resetting, a diffusive process whose amplitude is reset to the origin at random times, is a vividly studied strategy to optimize encounter dynamics, e.g., in chemical reactions. Here we generalize the resetting ... 
Exact distributions of the maximum and range of random diffusivity processes
(20210209)We study the extremal properties of a stochastic process $x_t$ defined by the Langevin equation ${\dot {x}}_{t}=\sqrt{2{D}_{t}}\enspace {\xi }_{t}$, in which $\xi_t$ is a Gaussian white noise with zero mean and $D_t$ is a ... 
Surrogate based Global Sensitivity Analysis of ADM1based Anaerobic Digestion Model
(2021)In order to calibrate the model parameters, Sensitivity Analysis routines are mandatory to rank the parameters by their relevance and fix to nominal values the least influential factors. Despite the high number of works ... 
Study of Wound Healing Dynamics by Single PseudoParticle Tracking in Phase Contrast Images Acquired in TimeLapse
(202103)Cellular contacts modify the way cells migrate in a cohesive group with respect to a free single cell. The resulting motion is persistent and correlated, with cells’ velocities selfaligning in time. The presence of a dense ... 
SHOULD I STAY OR SHOULD I GO? ZEROSIZE JUMPS IN RANDOM WALKS FOR LÉVY FLIGHTS
(202102)We study Markovian continuoustime random walk models for Lévy flights and we show an example in which the convergence to stable densities is not guaranteed when jumps follow a bimodal powerlaw distribution that is equal ... 
Exact firstpassage time distributions for three random diffusivity models
(20210104)We study the extremal properties of a stochastic process $x_t$ defined by a Langevin equation $\dot{x}= \sqrt{2D_o V (B_t )} \xi_t$, where $\xi$ is a Gaussian white noise with zero mean, $D_0$ is a constant scale factor, ... 
The random diffusivity approach for diffusion in heterogeneous systems
(20201216)The two hallmark features of Brownian motion are the linear growth $\langle x^2(t) \rangle = 2 D d t$ of the mean squared displacement (MSD) with diffusion coefficient $D$ in $d$ spatial dimensions, and the Gaussian ... 
Gut microbiota ecology: Biodiversity estimated from hybrid neutralniche model increases with health status and aging
(20201030)In this work we propose an index to estimate the gut microbiota biodiversity using a modeling approach with the aim of describing its relationship with health and aging. The gut microbiota, a complex ecosystem that links ... 
Universal spectral features of different classes of random diffusivity processes
(20200626)Stochastic models based on random diffusivities, such as the diffusing diffusivity approach, are popular concepts for the description of nonGaussian diffusion in heterogeneous media. Studies of these models typically ... 
A generalized Stefan model accounting for system memory and nonlocality
(202005)The Stefan problem, involving the tracking of an evolving phasechange front, is the prototypical example of a moving boundary problem. In basic one dimensional problems it is well known that the front advances as the ... 
A hypothesis about parallelism vs. seriality in dreams
(20191010)The current article discusses the hypothesis about parallelism vs. Seriality in dreams. The process of dream building implies the construction of a complex network of closely interrelated sources. On the other hand, the ... 
Gaussian processes in complex media: new vistas on anomalous diffusion
(201909)Normal or Brownian diffusion is historically identified by the linear growth in time of the variance and by a Gaussian shape of the displacement distribution. Processes departing from the at least one of the above conditions ... 
Front Propagation in Random Media
(2019)This PhD thesis deals with the problem of the propagation of fronts under random circumstances. A statistical model to represent the motion of fronts when are evolving in a media characterized by microscopical randomness ... 
Stochastic processes for anomalous diffusion
(2019)Anomalous diffusion is a diffusion process which Mean Square Displacement (MSD) is not a linear funtion of time, what is known as normal diffusion. When the relation is faster than linear, it is called superdiffusion and ... 
Singletrajectory spectral analysis of scaled Brownian motion
(201906)A standard approach to study timedependent stochastic processes is the power spectral density (PSD), an ensembleaveraged property defined as the Fourier transform of the autocorrelation function of the process in the ... 
Reduced description method in the kinetic theory of Brownian motion with active fluctuations
(20190901)We develop a microscopic approach to the kinetic theory of manyparticle systems with dissipative and potential interactions in presence of active fluctuations. The approach is based on a generalization of Bogolyubov–Peletminskii ... 
On the propagation of nonlinear transients of temperature and pore pressure in a thin porous boundary layer between two rocks.
(2019)The dynamics of transients of fluidrock temperature, pore pressure, pollutants in porous rocks are of vivid interest for fundamental problems in hydrological, volcanic, hydrocarbon systems, deep oil drilling. This can ... 
Restoring property of the MichelsonSivashinsky equation
(2019)In this paper we propose a derivation of the MichelsonSivashinsky (MS) equation that is based on front propagation only, in opposition to the classical derivation based also on the flow field. Hence, the characteristics ...