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Diffusion coefficients are essential microphysics input for modeling white dwarf evolution, as they impact phase separation at crystallization and sedimentary heat sources. Present schemes for computing diffusion coefficients are accurate…

Solar and Stellar Astrophysics · Physics 2022-04-06 M. E. Caplan , E. B. Bauer , I. F. Freeman

Diffusion-induced Ramsey narrowing that appears when atoms can leave the interaction region and repeatedly return without lost of coherence is investigated using strong collisions approximation. The effective diffusion equation is obtained…

Quantum Physics · Physics 2008-01-23 Alexander Romanenko , Leonid Yatsenko

We extend beyond the Euler scales the hydrodynamic theory for quantum and classical integrable models developed in recent years, accounting for diffusive dynamics and local entropy production. We review how the diffusive scale can be…

Statistical Mechanics · Physics 2019-04-24 Jacopo De Nardis , Denis Bernard , Benjamin Doyon

We introduce a gradient flow formulation of linear Boltzmann equations. Under a diffusive scaling we derive a diffusion equation by using the machinery of gradient flows.

Mathematical Physics · Physics 2020-09-03 Giada Basile , Dario Benedetto , Lorenzo Bertini

The macroscopic fluctuation theory provides a complete hydrodynamic description of non-equilibrium classical diffusive systems. As a first step towards a diffusive theory of open quantum systems, we show how to construct a microscopic open…

Statistical Mechanics · Physics 2020-06-24 Ohad Shpielberg

We show that long-time, long-distance fluctuations of plane-symmetric horizons exhibit universal hydrodynamic behavior. By considering classical fluctuations around black-brane backgrounds, we find both diffusive and shear modes. The…

High Energy Physics - Theory · Physics 2011-05-05 Pavel Kovtun , Dam T. Son , Andrei O. Starinets

In this paper we construct numerical schemes to approximate linear transport equations with slab geometry by diffusion equations. We treat both the case of pure diffusive scaling and the case where kinetic and diffusive scalings coexist.…

Numerical Analysis · Mathematics 2015-05-18 Qin Li , Jianfeng Lu , Weiran Sun

A new nonlinear Schroedinger equation is obtained explicitly from the fractal Brownian motion of a massive particle with a complex-valued diffusion constant. Real-valued energy (momentum) plane wave and soliton solutions are found in the…

Quantum Physics · Physics 2016-09-08 Carlos Castro , Jorge Mahecha , Boris Rodriguez

The diffusive viscous wave equation describes wave propagation in diffusive and viscous media. Examples include seismic waves traveling through the Earth's crust, taking into account of both the elastic properties of rocks and the…

Numerical Analysis · Mathematics 2025-01-13 Siyang Wang

In this paper we consider the one dimensional quantum hydrodynamics (QHD) system, with a genuine hydrodynamic approach. The global existence of weak solutions with large data has been obtained in [2, 3], in several space dimensions, by…

Analysis of PDEs · Mathematics 2021-01-26 Paolo Antonelli , Pierangelo Marcati , Hao Zheng

We present a hybrid computational method for simulating the dynamics of macromolecules in solution which couples a mesoscale solver for the fluctuating hydrodynamics (FH) equations with molecular dynamics to describe the macromolecule. The…

Soft Condensed Matter · Physics 2007-05-23 G. Giupponi , G. De Fabritiis , P. V. Coveney

We consider a Poisson equation in $\mathbb R^d$ for the elliptic operator corresponding to an ergodic diffusion process. Optimal regularity and smoothness with respect to the parameter are obtained under mild conditions on the coefficients.…

Probability · Mathematics 2020-09-11 Michael Röckner , Longjie Xie

We derive the hydrodynamic limit of a kinetic equation with a stochastic, short range perturbation of the velocity operator. Under some mixing hypotheses on the stochastic perturbation, we establish a diffusion-approximation result: the…

Analysis of PDEs · Mathematics 2020-10-01 Nils Caillerie , Julien Vovelle

The propagator of the discrete Schr\"odinger equation is computed and its properties are revealed through a Feynman path summation in discrete space. Initial data problems such as diffraction in discrete space and continuous time are…

Quantum Physics · Physics 2012-11-01 Emerson Sadurní

Time-dependent density-matrix propagation is used to demonstrate, in a schematic model of an open quantum system, that the complex potential approach and the Lindblad dissipative dynamics are \emph{not} equivalent. While the former…

Nuclear Theory · Physics 2010-05-12 Alexis Diaz-Torres

Shallow water surface flows commonly entrain sediments, resulting in scouring and/or deposition of the underlying substrate that may strongly influence the pattern of subsequent flow. These coupled phenomena, which can be investigated…

Computational Physics · Physics 2019-11-12 Haseeb Zia , Guy Simpson

Despite the fact that the calculations of drag coefficient and pressure distribution for airfoils can be completed by using Navier-Stoke's equation with help of experimental parameters and advanced computer programming, a simple theoretical…

Fluid Dynamics · Physics 2018-10-11 Maomao Zhao , Yufei Liu

We present a dual-resolution molecular dynamics (MD) simulation of liquid water employing a recently introduced Adaptive Resolution Scheme (AdResS). The spatially adaptive molecular resolution procedure allows for changing from a…

Soft Condensed Matter · Physics 2011-11-10 Silvina Matysiak , Cecilia Clementi , Matej Praprotnik , Kurt Kremer , Luigi Delle Site

In this manuscript we investigate the capabilities of the Discrete Dipole Approximation (DDA) to simulate scattering from particles that are much larger than the wavelength of the incident light, and describe an optimized publicly available…

Optics · Physics 2007-05-23 Maxim A. Yurkin , Valeri P. Maltsev , Alfons G. Hoekstra

We study passive scalar mixing by parallel shear flows in the presence of weak molecular diffusion. We recover the sharp uniform-in-diffusivity mixing rate for shear flows with finitely many critical points, recently proven in [1]. Our…

Analysis of PDEs · Mathematics 2026-03-11 Kyle L. Liss , Kunhui Luan