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We introduce an extension of the particle-in-cell (PIC) method that captures the Landau collisional effects in the Vlasov-Maxwell-Landau equations. The method arises from a regularisation of the variational formulation of the Landau…

Plasma Physics · Physics 2024-04-02 Rafael Bailo , José A. Carrillo , Jingwei Hu

In this note we identify a class of underactuated mechanical systems whose desired constant equilibrium position can be globally stabilised with the ubiquitous PID controller. The class is characterised via some easily verifiable conditions…

Dynamical Systems · Mathematics 2016-10-25 Jose Guadalupe Romero , Alejandro Donaire , Romeo Ortega

In this work, we show that for all statistical estimation problems, a natural MMSE instability (discontinuity) condition implies the failure of stable algorithms, serving as a version of OGP for estimation tasks. Using this criterion, we…

Statistics Theory · Mathematics 2026-03-24 Xifan Yu , Ilias Zadik

We present a straightforward and reliable continuous method for computing the full or a partial Lyapunov spectrum associated with a dynamical system specified by a set of differential equations. We do this by introducing a stability…

chao-dyn · Physics 2009-10-28 Freddy Christiansen , Hans Henrik Rugh

An electrostatic, implicit particle-in-cell (PIC) model for collisionless, fully magnetized, paraxial plasma expansions in a magnetic nozzle is introduced with exact charge, energy, and magnetic moment conservation properties. The approach…

Plasma Physics · Physics 2024-05-14 Pedro Jimenez , Luis Chacon , Mario Merino

A new spectral particle-in-cell (PIC) method for plasma modeling is presented and discussed. In the proposed scheme, the Fourier-Bessel transform is used to translate the Maxwell equations to the quasi-cylindrical spectral domain. In this…

Plasma Physics · Physics 2019-08-17 Igor A. Andriyash , Remi Lehe , Agustin Lifschitz

Plasma instabilities are a major concern in plasma science, for applications ranging from particle accelerators to nuclear fusion reactors. In this work, we consider the possibility of controlling such instabilities by adding an external…

Plasma Physics · Physics 2025-02-25 Lukas Einkemmer , Qin Li , Clément Mouhot , Yukun Yue

We present an alternative "encapsulated" formulation of the Selective Frequency Damping method for finding unstable equilibria of dynamical systems, which is particularly useful when analysing the stability of fluid flows. The formulation…

Fluid Dynamics · Physics 2015-06-18 Bastien E. Jordi , C. J. Cotter , Spencer J. Sherwin

This paper studies finite-time stability and instability theorems in probability sense for stochastic nonlinear systems. Firstly, a new sufficient condition is proposed to guarantee that the considered system has a global solution.…

Optimization and Control · Mathematics 2022-07-26 Weihai Zhang , Liqiang Yao

We present an efficient and accurate energy-conserving implicit particle-in-cell~(PIC) algorithm for the electrostatic Vlasov system, with particular emphasis on its high robustness for simulating complex plasma systems with multiple…

Computational Physics · Physics 2022-11-21 Zhuoning Li , Zhenli Xu , Zhiguo Yang

We present a unified theoretical framework for analyzing the stability and consistency of Physics-Informed Neural Networks (PINNs), grounded in operator coercivity, variational formulations, and non-asymptotic perturbation theory. PINNs…

Machine Learning · Computer Science 2025-09-04 Ronald Katende

Probabilistic cellular automata (PCA) are used to model a variety of discrete spatially extended systems undergoing parallel-updating. We propose an embedding of a number of classical nonequilibrium concepts in the PCA-world. We start from…

Statistical Mechanics · Physics 2017-01-17 Christian Maes

This paper addresses the robust stability of a boundary controlled system coupling two partial differential equations (PDEs), namely beam and string equations, in the presence of boundary and in-domain disturbances under the framework of…

Analysis of PDEs · Mathematics 2018-11-19 Jun Zheng , Hugo Lhachemi , Guchuan Zhu , David Saussi

We first propose the concept of Stepanov-like weighted pseudo-almost automorphic on time-space scales and we apply this type of oscillation to high-order BAM neural networks with mixed delays. Then, we study the existence and exponential…

Dynamical Systems · Mathematics 2018-03-15 Adnène Arbi

The formalism of Ursell operators provides a self-consistent integral equation for the one-particle reduced operator. In three dimensions this technique yields values of the shift in the Bose-Einstein condensation (BEC) transition…

Statistical Mechanics · Physics 2007-05-23 W. J. Mullin , M. Holzmann , F. Laloe

Physical processes evolving in both time and space are often modeled using Partial Differential Equations (PDEs). Recently, it has been shown how stability analysis and control of coupled PDEs in a single spatial variable can be more…

Analysis of PDEs · Mathematics 2026-05-20 Declan S. Jagt , Matthew M. Peet

Traditionally, finite differences and finite element methods have been by many regarded as the basic tools for obtaining numerical solutions in a variety of quantum mechanical problems emerging in atomic, nuclear and particle physics,…

Quantum Physics · Physics 2008-11-26 A. Deloff

We consider the numerical approximation of the filtering problem in high dimensions, that is, when the hidden state lies in $\mathbb{R}^d$ with $d$ large. For low dimensional problems, one of the most popular numerical procedures for…

Computation · Statistics 2014-12-12 Alex Beskos , Dan Crisan , Ajay Jasra , Kengo Kamatani , Yan Zhou

The linear and nonlinear characteristics of the electron cyclotron drift instability (ECDI) have been studied through the particle-in-cell (PIC) and continuum Vlasov simulation methods in connection with the effects of the azimuthal length…

Position based dynamics is a powerful technique for simulating a variety of materials. Its primary strength is its robustness when run with limited computational budget. We develop a novel approach to address problems with PBD for…

Graphics · Computer Science 2023-06-16 Yizhou Chen , Yushan Han , Jingyu Chen , Joseph Teran