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In recent years, discrete fractional epidemic models with reaction-diffusion have become increasingly popular in the literature, not only for its necessity of numerical simulation, but also for its defined physical processes. In this paper,…

Numerical Analysis · Mathematics 2022-08-16 Lu Zhenzhen , Yu Yongguang , Xu Weiyi , Ren Guojian , Meng Xiangyun

Diffusion models generate samples by incrementally reversing a process that turns data into noise. We show that when the step size goes to zero, the reversed process is invariant to the distribution of these increments. This reveals a…

Machine Learning · Computer Science 2024-12-12 Henry Li

At non-equilibrium phase transitions into absorbing (trapped) states, it is well known that the directed percolation (DP) critical scaling is shared by two classes of models with a single (S) absorbing state and with infinitely many (IM)…

Statistical Mechanics · Physics 2009-11-13 Su-Chan Park , Hyunggyu Park

A systematic theory for the diffusion--limited reaction processes $A + A \to 0$ and $A \to (m+1) A$ is developed. Fluctuations are taken into account via the field--theoretic dynamical renormalization group. For $m$ even the mean field rate…

Statistical Mechanics · Physics 2009-10-28 John Cardy , Uwe C. Täuber

Anomalous dynamics in which local perturbations spread faster than diffusion are ubiquitously observed in the long-time behavior of a wide variety of systems. Here, the manner by which such systems evolve towards their asymptotic…

Statistical Mechanics · Physics 2020-04-09 Asaf Miron

Modeling long-range epidemic spreading in a random environment, we consider a quenched disordered, $d$-dimensional contact process with infection rates decaying with the distance as $1/r^{d+\sigma}$. We study the dynamical behavior of the…

Disordered Systems and Neural Networks · Physics 2015-04-02 R. Juhász , I. A. Kovács , F. Iglói

In this paper, we consider reaction-diffusion epidemic models with mass action or standard incidence mechanism and study the impact of limiting population movement on disease transmissions. We set either the dispersal rate of the…

Analysis of PDEs · Mathematics 2023-12-19 Rachidi Salako , Yixiang Wu

We study the nonequilibrium critical behavior of the pair contact process with diffusion (PCPD) by means of nonperturbative functional renormalization group techniques. We show that usual perturbation theory fails because the effective…

Statistical Mechanics · Physics 2014-07-29 Damien Gredat , Hugues Chaté , Ivan Dornic , Bertrand Delamotte

In the present paper, our goal is to establish a framework for the mathematical modelling and the analysis of the spread of an epidemic in a large population commuting regularly, typically along a time-periodic pattern, as is roughly…

Populations and Evolution · Quantitative Biology 2024-08-29 Pierre-Alexandre Bliman , Boureima Sangaré , Assane Savadogo

We investigated the phase transition behavior of a binary spreading process in two dimensions for different particle diffusion strengths ($D$). We found that $N>2$ cluster mean-field approximations must be considered to get consistent…

Statistical Mechanics · Physics 2009-11-07 G. Odor , M. C. Marques , M. A. Santos

We consider the development of hyperbolic transport models for the propagation in space of an epidemic phenomenon described by a classical compartmental dynamics. The model is based on a kinetic description at discrete velocities of the…

Physics and Society · Physics 2021-04-12 Giulia Bertaglia , Lorenzo Pareschi

A recent study of conserved Manna model, with both discrete and continuous variable, indicates that absorbing phase transitions therein belong to the directed percolation (DP) universality class. In this context we revisit critical…

Statistical Mechanics · Physics 2013-07-16 Urna Basu , Mahashweta Basu , P. K. Mohanty

Recent advancements in diffusion models have demonstrated significant success in unsupervised anomaly segmentation. For anomaly segmentation, these models are first trained on normal data; then, an anomalous image is noised to an…

Computer Vision and Pattern Recognition · Computer Science 2025-08-08 Mehrdad Moradi , Kamran Paynabar

Different branching and annihilating random walk models are investigated by cluster mean-field method and simulations in one and two dimensions. In case of the A -> 2A, 2A -> 0 model the cluster mean-field approximations show diffusion…

Statistical Mechanics · Physics 2009-11-10 Geza Odor

We propose the deterministic rate equation of three-species in the reaction - diffusion system. For this case, our purpose is to carry out the decay process in our three-species reaction-diffusion model of the form $A+B+C\to D$. The…

Statistical Mechanics · Physics 2009-10-31 Kyungsik Kim , K. H. Chang , Y. S. Kong

The phase transition of the one-dimensional, diffusive pair contact process (PCPD) is investigated by N cluster mean-field approximations and high precision simulations. The N=3,4 cluster approximations exhibit smooth transition line to…

Statistical Mechanics · Physics 2009-11-07 Geza Odor

Percolation is a paradigmatic model in disordered systems and has been applied to various natural phenomena. The percolation transition is known as one of the most robust continuous transitions. However, recent extensive studies have…

Statistical Mechanics · Physics 2015-07-13 Y. S. Cho , B. Kahng

Epidemic processes are common out-of-equilibrium phenomena of broad interdisciplinary interest. Recently, dynamic message-passing (DMP) has been proposed as an efficient algorithm for simulating epidemic models on networks, and in…

Physics and Society · Physics 2015-09-30 Munik Shrestha , Samuel V. Scarpino , Cristopher Moore

We study the nonequilibrium phase transitions from the absorbing phase to the active phase for the model of disease spreading (Susceptible-Infected-Refractory-Susceptible (SIRS)) on a regular one dimensional lattice. In this model,…

Statistical Mechanics · Physics 2023-08-15 M. Ali Saif

We develop a framework for non-asymptotic analysis of deterministic samplers used for diffusion generative modeling. Several recent works have analyzed stochastic samplers using tools like Girsanov's theorem and a chain rule variant of the…

Machine Learning · Computer Science 2023-03-07 Sitan Chen , Giannis Daras , Alexandros G. Dimakis