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In the evolving voter model, when an individual interacts with a neighbor having an opinion different from theirs, they will with probability $1-\alpha$ imitate the neighbor but with probability $ \alpha$ will sever the connection and…

Probability · Mathematics 2016-06-28 Anirban Basak , Rick Durrett , Yuan Zhang

Q-conditional symmetries (nonclassical symmetries) for a general class of two-component reaction-diffusion systems with constant diffusivities are studied. Using the recently introduced notion of Q-conditional symmetries of the first type…

Mathematical Physics · Physics 2019-09-17 Roman Cherniha , Vasyl' Davydovych

The q-voter model is a spin-flip system in which the rate of flipping to type i is given by the qth power of the proportion of nearest neighbours in type i for $i=0,1$. If $q=1$ it reduces to the classical voter model. We show that in the…

Probability · Mathematics 2023-11-27 Ted Cox , Ed Perkins

Diffusion models are generative models that have recently demonstrated impressive performances in terms of sampling quality and density estimation in high dimensions. They rely on a forward continuous diffusion process and a backward…

Machine Learning · Computer Science 2024-02-07 Christian Horvat , Jean-Pascal Pfister

We consider statistical inference for a class of dynamic mixed-effect models described by stochastic differential equations whose drift and diffusion coefficients simultaneously depend on fixed- and random-effect parameters. Assuming that…

Statistics Theory · Mathematics 2025-12-30 Maud Delattre , Hiroki Masuda

The mean square displacement per collision of a molecule immersed in a gas at equilibrium is given by its mean square displacement between two consecutive collisions (mean square free path) corrected by a prefactor in the form of a series.…

Soft Condensed Matter · Physics 2024-07-03 Santos Bravo Yuste , Rubén Gómez González , Vicente Garzó

We study systems of reaction-diffusion equations with discontinuous spatially distributed hysteresis in the right-hand side. The input of hysteresis is given by a vector-valued function of space and time. Such systems describe hysteretic…

Analysis of PDEs · Mathematics 2013-09-27 Pavel Gurevich , Sergey Tikhomirov

We introduce a class of probability measure-valued diffusions, coined polynomial, of which the well-known Fleming--Viot process is a particular example. The defining property of finite dimensional polynomial processes considered by Cuchiero…

Probability · Mathematics 2018-07-10 Christa Cuchiero , Martin Larsson , Sara Svaluto-Ferro

We consider conservative cross-diffusion systems for two species where individual motion rates depend linearly on the local density of the other species. We develop duality estimates and obtain stability and approximation results. We first…

Analysis of PDEs · Mathematics 2024-10-30 Vincent Bansaye , Ayman Moussa , Felipe Muñoz-Hernández

The q-voter model, a variant of the classic voter model, has been analyzed by several authors: while allowing to study opinion dynamics, this model is also believed to be one of the most representative among the many defined in the wide…

Physics and Society · Physics 2015-10-26 Marco Alberto Javarone , Tiziano Squartini

In this paper we investigate the variable coefficient two-sided fractional diffusion, advection, reaction equations on a bounded interval. It is known that the fractional diffusion operator may lose coercivity due to the variable…

Numerical Analysis · Mathematics 2022-03-23 Xiangcheng Zheng , V. J. Ervin , Hong Wang

We propose an alternative method for one-dimensional continuum diffusion models with spatially variable (heterogeneous) diffusivity. Our method, which extends recent work on stochastic diffusion, assumes the constant-coefficient homogenized…

Computational Physics · Physics 2019-12-18 Elliot J. Carr

The dispersion of inertial particles continuously emitted from a point source is analytically investigated in the limit of small inertia. Our focus is on the evolution equation of the particle joint probability density function p(x,v,t), x…

Exactly Solvable and Integrable Systems · Physics 2009-06-01 Marco Martins Afonso , Andrea Mazzino

We study a large class of 1D reaction diffusion models with quenched disorder using a real space renormalization group method (RSRG) which yields exact results at large time. Particles (e.g. of several species) undergo diffusion with random…

Condensed Matter · Physics 2009-10-31 Pierre Le Doussal , Cecile Monthus

Voter models are well known in the interdisciplinary community, yet they haven't been studied from the perspective of anomalous diffusion. In this paper we show that the original voter model exhibits ballistic regime. Non-linear…

Statistical Mechanics · Physics 2022-02-22 Rytis Kazakevičius , Aleksejus Kononovicius

Score-based generative models like the diffusion model have been testified to be effective in modeling multi-modal data from image generation to reinforcement learning (RL). However, the inference process of diffusion model can be slow,…

Machine Learning · Computer Science 2024-03-18 Zihan Ding , Chi Jin

In this work, we explore a time-fractional diffusion equation of order $\alpha \in (0,1)$ with a stochastic diffusivity parameter. We focus on efficient estimation of the expected values (considered as an infinite dimensional integral on…

Numerical Analysis · Mathematics 2024-09-04 Josef Dick , Hecong Gao , William McLean , Kassem Mustapha

In this work, we propose a positivity-preserving scheme for solving two-dimensional advection-diffusion equations including mixed derivative terms, in order to improve the accuracy of lower-order methods. The solution to these equations, in…

Computational Physics · Physics 2018-05-14 Erasmus J. du Toit , Martin R. O'Brien , Roddy G. L. Vann

We assume that we observe $N$ independent copies of a diffusion process on a time-interval $[0,2T]$. For a given time $t$, we estimate the transition density $p_t(x,y)$, namely the conditional density of $X_{t + s}$ given $X_s = x$, under…

Statistics Theory · Mathematics 2025-05-01 Fabienne Comte , Nicolas Marie

We scrutinize the anomalies in diffusion observed in an extended long-range system of classical rotors, the HMF model. Under suitable preparation, the system falls into long-lived quasi-stationary states presenting super-diffusion of rotor…

Statistical Mechanics · Physics 2009-11-11 Luis G. Moyano , Celia Anteneodo