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We consider the kinetic transport equation that arise in the Boltzmann-Grad limit of the two-dimensional periodic Lorentz Gas. This equation has been obtained by extending the phase space of positions and velocities through the introduction…

Mathematical Physics · Physics 2026-03-17 Francesca Pieroni

Diffusion with stochastic transport is investigated here when the random driving process is a very general Gaussian process, including Fractional Brownian motion. The purpose is the comparison with a deterministic PDE, which in certain…

Probability · Mathematics 2026-04-20 Franco Flandoli , Francesco Russo

The nonlinear boson diffusion equation is taken as a basis to account for the fast thermalization of gluons in the initial stages of relativistic heavy-ion collisions. For constant drift and diffusion coefficients with schematic initial…

High Energy Physics - Phenomenology · Physics 2025-11-25 J. Rössler , G. Wolschin

We study a 1D transport equation with nonlocal velocity and show the formation of singularities in finite time for a generic family of initial data. By adding a diffusion term the finite time singularity is prevented and the solutions exist…

Analysis of PDEs · Mathematics 2007-06-14 Antonio Cordoba , Diego Cordoba , Marco A. Fontelos

The system of hydrodynamic-type equations is derived from Alexeev's generalized Boltzmann kinetic equation by two-side distribution function for a stratified gas in gravity field. It is applied to a problem of ultrasound propagation and…

Fluid Dynamics · Physics 2007-05-23 Sergey B. Leble , Maxim A. Solovchuk

We discuss the non--linear growth of the kurtosis of the smoothed peculiar velocity field (along an arbitrary direction), in an Einstein--de Sitter universe, induced by Gaussian primordial density fluctuations. Applying the perturbative…

Astrophysics · Physics 2008-11-26 Paolo Catelan , Lauro Moscardini

The Lagrangian dynamics of a single fluid element within a self-gravitational matter field is intrinsically non-local due to the presence of the tidal force. This complicates the theoretical investigation of the non-linear evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-23 Xin Wang , Alex Szalay

The Graetz problem is a convection-diffusion equation in a pipe invariant along a direction. The contribution of the present work is to propose a mathematical analysis of the Neumann, Robin and periodic boundary condition on the boundary of…

Numerical Analysis · Mathematics 2018-03-05 Valention Debarnot , Jérôme Fehrenbach , Frédéric de Gournay , Léo Martire

We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards 2d absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously…

Disordered Systems and Neural Networks · Physics 2009-11-10 J. S. Andrade , H. F. da Silva , M. Baquil , B. Sapoval

Fractional kinetic equations employ non-integer calculus to model anomalous relaxation and diffusion in many systems. While this approach is well explored, it so far failed to describe an important class of transport in disordered systems.…

Statistical Mechanics · Physics 2021-01-04 Wanli Wang , Eli Barkai

We demonstrate that the Einstein relation for the diffusion of a particle in the random energy landscape with the Gaussian density of states is an exclusive 1D property and does not hold in higher dimensions. We also consider the analytical…

Disordered Systems and Neural Networks · Physics 2020-02-21 S. V. Novikov

This paper investigates the nonlinear dynamics of Newton's problem of minimal resistance in radial fields. We move beyond classical translational symmetry to analyze two non-equilibrium scenarios: a scale-invariant free expansion and an…

Fluid Dynamics · Physics 2026-05-15 Rafael López

The dynamical formulation of the optimal transport can be extended through various choices of the underlying geometry (kinetic energy), and the regularization of density paths (potential energy). These combinations yield different…

Machine Learning · Computer Science 2024-07-04 Kirill Neklyudov , Rob Brekelmans , Alexander Tong , Lazar Atanackovic , Qiang Liu , Alireza Makhzani

We study the motion of isentropic gas in nozzles. This is a major subject in fluid dynamics. In fact, the nozzle is utilized to increase the thrust of rocket engines. Moreover, the nozzle flow is closely related to astrophysics. These…

Analysis of PDEs · Mathematics 2017-02-21 Naoki Tsuge

In this paper we consider the evolution of sets by a fractional mean curvature flow. Our main result states that for any dimension $n > 2$, there exists an embedded surface in $\mathbb R^n$ evolving by fractional mean curvature flow, which…

Differential Geometry · Mathematics 2016-07-29 Eleonora Cinti , Carlo Sinestrari , Enrico Valdinoci

We consider the parabolic polyharmonic diffusion and $L^2$-gradient flows of the $m$-th arclength derivative of curvature for regular closed curves evolving with generalised Neumann boundary conditions. In the polyharmonic case, we prove…

Analysis of PDEs · Mathematics 2020-01-20 James McCoy , Glen Wheeler , Yuhan Wu

We show that the second accelerating expansion of the universe appears smoothly from the decelerating universe remarkably after the initial inflation in the two-dimensional soluble semi-classical dilaton gravity along with the modified…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Wontae Kim , Edwin J. Son

We study the existence of global weak solutions of a nonlinear transport-diffusion equation with a fractional derivative in the time variable and under some extra hypotheses, we also study some regularity properties for this type of…

Analysis of PDEs · Mathematics 2022-03-25 Diego Chamorro , Miguel Yangari

This paper is devoted to the diffusive limit of the nonlinear radiative heat transfer system with curved boundary domain (\textit{two dimensional disk}). The solution constructed in \cite{ghattassi2022convergence} by the leading order…

Analysis of PDEs · Mathematics 2023-05-30 Mohamed Ghattassi , Xiaokai Huo , Nader Masmoudi

Beckmann's problem in optimal transport minimizes the total squared flux in a continuous transport problem from a source to a target distribution. In this article, the regularity theory for solutions to Beckmann's problem in optimal…

Analysis of PDEs · Mathematics 2026-03-23 Hanno Gottschalk , Tobias J. Riedlinger