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Related papers: On generalization of quasidiffusions

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While it is very common to model diffusion as a random walk by assuming memorylessness of the trajectory and diffusive step lengths, these assumptions can lead to significant errors. This paper describes the extent to which a physical…

Statistical Mechanics · Physics 2025-08-07 Ludovico Cademartiri

We study the dynamics of a generalization of quantum coin walk on the line which is a natural model for a diffusion modified by quantum or interference effects. In particular, our results provide surprisingly simple explanations to…

Quantum Physics · Physics 2007-05-23 A. Wojcik , T. Luczak , P. Kurzynski , A. Grudka , M. Bednarska

In this work, several convergence results are established for nearly critical self-excited systems in which event arrivals are described by multivariate marked Hawkes point processes. Under some mild high-frequency assumptions, the rescaled…

Probability · Mathematics 2024-01-31 Wei Xu

We study a one dimensional generalization of the exponential trap model using both numerical simulations and analytical approximations. We obtain the asymptotic shape of the average diffusion front in the sub-diffusive phase. Our central…

Disordered Systems and Neural Networks · Physics 2009-11-07 E. M. Bertin , J. -P. Bouchaud

We analyze quantal Brownian motion in $d$ dimensions using the unified model for diffusion localization and dissipation, and Feynman-Vernon formalism. At high temperatures the propagator possess a Markovian property and we can write down an…

Condensed Matter · Physics 2009-10-31 Doron Cohen

We consider inhomogeneous branching diffusions on an infinite domain of $\mathbb{R}^d$. The first aim of this article is to derive a general criterium under which the size process (number of particles) and the genealogy of the particle…

Probability · Mathematics 2024-02-08 Félix Foutel-Rodier , Emmanuel Schertzer , Julie Tourniaire

The effective diffusion of Brownian particles in periodic potential has been a central topic in nonequilibrium statistical physcis. A classical result is the Lifson formula which provides the effective diffusion constant in periodic…

Statistical Mechanics · Physics 2026-01-22 Sang Yang , Zhixin Peng

Stochastic diffusion is the noisy and uncertain process through which dynamics like epidemics, or agents like animal species, disperse over a larger area. Understanding these processes is becoming increasingly important as we attempt to…

This paper establishes the global asymptotic equivalence, in the sense of the Le Cam $\Delta$-distance, between scalar diffusion models with unknown drift function and small variance on the one side, and nonparametric autoregressive models…

Probability · Mathematics 2015-03-05 Ester Mariucci

This article studies the quasi-stationary behaviour of absorbed one-dimensional diffusions. We obtain necessary and sufficient conditions for the exponential convergence to a unique quasi-stationary distribution in total variation,…

Probability · Mathematics 2017-03-03 Nicolas Champagnat , Denis Villemonais

Diffusion models have emerged as powerful generative tools, rivaling GANs in sample quality and mirroring the likelihood scores of autoregressive models. A subset of these models, exemplified by DDIMs, exhibit an inherent asymmetry: they…

Computer Vision and Pattern Recognition · Computer Science 2024-01-24 Yixuan Wang , Shuangyin Li

A discrete-time two-dimensional quasi-birth-and-death process (2d-QBD process), $\{{\boldsymbol{Y}}_n\}=\{(X_{1,n},X_{2,n},J_n)\}$, is a two-dimensional skip-free random walk $\{(X_{1,n},X_{2,n})\}$ on $\mathbb{Z}_+^2$ with a supplemental…

Probability · Mathematics 2018-07-23 Toshihisa Ozawa , Masahiro Kobayashi

This chapter aims at emphasizing the crucial role of partial reactivity of a catalytic surface or a target molecule in diffusion-controlled reactions. We discuss various microscopic mechanisms that lead to imperfect reactions, the Robin…

Chemical Physics · Physics 2019-11-05 Denis S. Grebenkov

With the incorporation of the UNet architecture, diffusion probabilistic models have become a dominant force in image generation tasks. One key design in UNet is the skip connections between the encoder and decoder blocks. Although skip…

Machine Learning · Computer Science 2024-02-26 Jiajun Ma , Shuchen Xue , Tianyang Hu , Wenjia Wang , Zhaoqiang Liu , Zhenguo Li , Zhi-Ming Ma , Kenji Kawaguchi

Nonergodicity observed in single-particle tracking experiments is usually modeled by transient trapping rather than spatial disorder. We introduce models of a particle diffusing in a medium consisting of regions with random sizes and random…

Soft Condensed Matter · Physics 2014-09-23 P. Massignan , C. Manzo , J. A. Torreno-Pina , M. F. García-Parajo , M. Lewenstein , G. J. Lapeyre

Diffusion models have demonstrated remarkable empirical success in the recent years and are considered one of the state-of-the-art generative models in modern AI. These models consist of a forward process, which gradually diffuses the data…

Machine Learning · Computer Science 2026-01-07 Xingyu Xu , Ziyi Zhang , Yorie Nakahira , Guannan Qu , Yuejie Chi

We study slow-subdiffusion in comparison to subdiffusion. Both of the processes are treated as random walks and can be described within continuous time random walk formalism. However, the probability density of the waiting time of a random…

Statistical Mechanics · Physics 2013-01-22 K. D. Lewandowska , Tadeusz Kosztołowicz

We address the hydrodynamics of operator spreading in interacting integrable lattice models. In these models, operators spread through the ballistic propagation of quasiparticles, with an operator front whose velocity is locally set by the…

Statistical Mechanics · Physics 2018-12-26 Sarang Gopalakrishnan , David A. Huse , Vedika Khemani , Romain Vasseur

Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions, $\phi$, in the vicinity of the jamming transition at $\phi_{c}$. Various diffusion properties are computed…

Statistical Mechanics · Physics 2015-09-02 Dan S. Bolintineanu , Gary S. Grest , Jeremy B. Lechman , Leonardo E. Silbert

We consider a processor sharing queue where the number of jobs served at any time is limited to $K$, with the excess jobs waiting in a buffer. We use random counting measures on the positive axis to model this system. The limit of this…

Probability · Mathematics 2012-07-02 Jiheng Zhang , J. G. Dai , Bert Zwart