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Knowledge of the noise distribution in diffusion MRI is the centerpiece to quantify uncertainties arising from the acquisition process. Accurate estimation beyond textbook distributions often requires information about the acquisition…

Image and Video Processing · Electrical Eng. & Systems 2020-07-07 Samuel St-Jean , Alberto De Luca , Chantal M. W. Tax , Max A. Viergever , Alexander Leemans

The Boltzmann distribution of an ideal gas is determined by the Hamiltonian function generating single particle dynamics. Systems with higher complexity often exhibit topological constraints, which are independent of the Hamiltonian and may…

General Relativity and Quantum Cosmology · Physics 2021-07-29 Naoki Sato

The mechanism of diffusing diffusivity predicts that, in environments where the diffusivity changes gradually, the displacement distribution becomes non-Gaussian, even though the mean-squared displacement (MSD) grows linearly with time.…

Statistical Mechanics · Physics 2017-10-18 Mpumelelo Matse , Mykyta V. Chubynsky , John Bechhoefer

The diffusing-diffusivity mechanism proposed by Chubynsky and Slater [PRL 113, 098302, 2014] predicts that, in environments where the diffusivity changes gradually, the displacement distribution becomes non-Gaussian, even though the…

Biological Physics · Physics 2016-03-03 Mpumelelo Matse , John Bechhoefer

A new approach to the modeling of nonfree particle diffusion is presented. The approach uses a general setup based on geometric graphs (networks of curves), which means that particle diffusion in anything from arrays of barriers and pore…

Statistical Mechanics · Physics 2018-04-05 Niels Buhl

Recent advances in diffusion models attempt to handle conditional generative tasks by utilizing a differentiable loss function for guidance without the need for additional training. While these methods achieved certain success, they often…

Machine Learning · Computer Science 2024-07-08 Lingxiao Yang , Shutong Ding , Yifan Cai , Jingyi Yu , Jingya Wang , Ye Shi

In the last decade Diffusing Wave Spectroscopy (DWS) has emerged as a powerful tool to study turbid media. In this article we develop the formalism to describe light diffusion in general anisotropic turbid media. We give explicit formulas…

Soft Condensed Matter · Physics 2009-10-28 Holger Stark , Tom C. Lubensky

Based on a re-formulation of the classical explanation of quantum mechanical Gaussian dispersion (Groessing et al. 2010) as well as interference of two Gaussians (Groessing et al. 2012), we present a new and more practical way of their…

Quantum Physics · Physics 2013-04-11 Johannes Mesa Pascasio , Siegfried Fussy , Herbert Schwabl , Gerhard Groessing

The impact of the third (skewness) and fourth (kurtosis) reduced centered moments on the statistical modeling of E1 lines in complex atomic spectra is investigated through the use of Gram-Charlier, Normal Inverse Gaussian and Generalized…

Atomic Physics · Physics 2015-05-13 Jean-Christophe Pain , Franck Gilleron , Jacques Bauche , Claire Bauche-Arnoult

This paper introduces a new sparse spatio-temporal structured Gaussian process regression framework for online and offline Bayesian inference. This is the first framework that gives a time-evolving representation of the interdependencies…

Machine Learning · Statistics 2018-08-01 Danil Kuzin , Olga Isupova , Lyudmila Mihaylova

Practical diffusion sampling is a numerical approximation problem: under a fixed inference budget, one must simulate a reverse-time ODE or SDE using only a limited number of denoising steps, so discretization error is often the dominant…

Machine Learning · Computer Science 2026-05-12 Samuel Hurault , Thomas Moreau , Gabriel Peyré

Diffusing-wave spectroscopy is a powerful technique which consists in measuring the temporal correlation function of the intensity of light multiply scattered by a medium. In this paper, we apply this technique to cold atoms under purely…

A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces…

Of primary interest in this paper is the numerical approximation of a time dependent fractional, in space, diffusion equation where the domain is assumed to be nonhomogeneous, having different axial diffusion coefficients. This work is…

Numerical Analysis · Mathematics 2026-05-12 T. Catoe , V. J. Ervin

We present a nonparametric Bayesian framework to infer radial distribution functions from experimental scattering measurements with uncertainty quantification using non-stationary Gaussian processes. The Gaussian process prior mean and…

Chemical Physics · Physics 2026-02-03 Harry W. Sullivan , Brennon L. Shanks , Matej Cervenka , Michael P. Hoepfner

Diffusion models have attracted a lot of attention in recent years. These models view speech generation as a continuous-time process. For efficient training, this process is typically restricted to additive Gaussian noising, which is…

Machine Learning · Computer Science 2025-10-14 Xiaozhou Tan , Minghui Zhao , Anton Ragni

We introduce a new universality class of one-dimensional iteration model giving rise to self-similar motion, in which the Feigenbaum constants are generalized as self-similar rates and can be predetermined. The curves of the mean-square…

Statistical Mechanics · Physics 2010-05-06 Zhifu Huang , Guozhen Su , Qiuping A Wang , Jincan Chen

This paper uses dynamical invariants to describe the evolution of collisionless systems subject to time-dependent gravitational forces without resorting to maximum-entropy probabilities. We show that collisionless relaxation can be viewed…

Astrophysics of Galaxies · Physics 2015-06-03 Jorge Peñarrubia

We theoretically analyze diffusion trajectories of an anisotropic object moving on a two dimensional space in the absence of an external field. In determining diffusion parameters associated with the shape anisotropy, we devise a measure…

Statistical Mechanics · Physics 2015-08-31 Sunghan Roh , Juyeon Yi , Yong Woon Kim

Using a discrete wavelet based space-scale decomposition (SSD), the spectrum of the skewness and kurtosis is developed to describe the non-Gaussian signatures in cosmologically interesting samples. Because the basis of the discrete wavelet…

Astrophysics · Physics 2007-05-23 Jesus Pando , Li-Zhi Fang