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The recently developed energy conserving semi-implicit method (ECsim) for PIC simulation is applied to multiple scale problems where the electron-scale physics needs to be only partially retained and the interest is on the macroscopic or…

Computational Physics · Physics 2017-05-24 Giovanni Lapenta , Diego Gonzalez-Herrero , Elisabetta Boella

Modern particle-in-cell (PIC) codes have become an integral tool in plasma astrophysics. As most plasma phenomena grow from initially small instabilities, it is important to ensure PIC codes can suppress noise and ensure that any growing…

High Energy Astrophysical Phenomena · Physics 2026-05-18 Ludwig M. Böss , Arno Vanthieghem , Hayk Hakobyan , Evgeny A. Gorbunov , Damiano Caprioli

Due to significant manufacturing process variations, the performance of integrated circuits (ICs) has become increasingly uncertain. Such uncertainties must be carefully quantified with efficient stochastic circuit simulators. This paper…

Computational Engineering, Finance, and Science · Computer Science 2014-09-18 Zheng Zhang , Ibrahim , M. Elfadel , Luca Daniel

This paper presents an $\mathcal{H}_\infty$ model matching control-based approach to the problem of power hardware-in-the-loop (PHIL) interfacing. The objective is to interconnect a grid simulation and a physical device via an interface in…

Systems and Control · Electrical Eng. & Systems 2025-11-12 Jonathan Eid , Ashley Meagher , Dmitry Rimorov , Anil Kumar Bonala , Rajendra Thike , James Richard Forbes

We present a finite-time framework for identifying stable and unstable linear time-invariant (LTI) systems from a single closed-loop input-output trajectory. The method does not require knowledge of the stabilizing controller, an…

Systems and Control · Electrical Eng. & Systems 2026-05-26 Ahmad Al-Tawaha , Ming Jin , Khaled F. Aljanaideh

Physics-Informed Neural Networks have become a powerful mesh-free method for solving partial differential equations, but their performance is often limited by spectral bias. Specifically, in standard MLPs used in PINNs, the global parameter…

Machine Learning · Computer Science 2026-05-04 Jianfeng Li , Feng Wang , Ke Tang

Self consistent quantum approaches are used to study the instabilities of finite nuclear systems. The frequencies of multipole density fluctuations are determined as a function of dilution and temperature, for several isotopes. The spinodal…

Nuclear Theory · Physics 2009-11-07 M. Colonna , Ph. Chomaz , S. Ayik

Neural operators on irregular meshes face a fundamental tension. Spectral positional encodings, the natural choice for capturing geometry, require cubic-complexity eigendecomposition and inadvertently break gauge invariance through…

Machine Learning · Computer Science 2026-05-13 Mattia Rigotti , Nicholas Thumiger , Thomas Frick

Graph states are entangled states that are essential for quantum information processing. As experimental advances enable the realization of large-scale graph states, efficient fidelity estimation methods are crucial for assessing their…

This paper deals with the numerical resolution of the Vlasov-Poissonsystem with a strong external magnetic field by Particle-In-Cell(PIC) methods. In this regime, classical PIC methods are subject tostability constraints on the time and…

Numerical Analysis · Mathematics 2015-11-24 Francis Filbet , Luis Miguel Rodrigues

Many problems in astrophysics involve relativistic outflows. The plasma dynamics in these scenarios is critical to determine the conditions for the self-consistent evolution of the fields and particle acceleration. Advances in computer…

Astrophysics · Physics 2014-10-13 L. O. Silva

Physics-Informed Neural Networks (PINNs) often struggle to train reliably on stiff and oscillatory dynamical systems due to poor optimization conditioning. While prior work has emphasized representational remedies such as spectral…

Machine Learning · Computer Science 2026-05-07 Isabela M. Yepes , Pavlos Protopapas

A method of Parity-Time (PT)-symmetry analysis is introduced to study the high dimensional, complicated parameter space of drift wave instabilities. We show that spontaneous PT-symmetry breaking leads to the Ion Temperature Gradient (ITG)…

Plasma Physics · Physics 2021-08-04 Hong Qin , Yichen Fu , Alexander S. Glasser , Asher Yahalom

Electric power systems are undergoing fundamental change. The shift to inverter-based generation challenges frequency stability, while growing digitalisation heightens vulnerability to errors and attacks. Here we identify an emerging risk…

We present the parallel particle-in-cell (PIC) code Apar-T and, more importantly, address the fundamental question of the relations between the PIC model, the Vlasov-Maxwell theory, and real plasmas. First, we present four validation tests:…

High Energy Astrophysical Phenomena · Physics 2013-11-12 Mickaël Melzani , Christophe Winisdoerffer , Rolf Walder , Doris Folini , Jean M. Favre , Stefan Krastanov , Peter Messmer

We study numerically and analytically the instabilities associated with phase separation in a solid layer on which an external material ux is imposed. The first instability is localized within a boundary layer at the exposed free surface by…

Materials Science · Physics 2018-01-17 Esteban Meca , Andreas Münch , Barbara Wagner

The entropic measure for analysis of grey level inhomogeneity (GLI) is proposed as a function of length scale. It allows us to quantify the statistical dissimilarity of the actual macrostate and the maximizing entropy of the reference one.…

Statistical Mechanics · Physics 2009-04-10 R. Piasecki

The numerical instability observed in the Electromagnetic-Particle-in-cell (EM-PIC) simulations with a plasma drifting with relativistic velocities is studied using both theory and computer simulations. We derive the numerical dispersion…

Developing particle-in-cell (PIC) methods using finite element basis sets, and without auxiliary divergence cleaning methods, was a long standing problem until recently. It was shown that if consistent spatial basis functions are used, one…

Plasma Physics · Physics 2021-10-04 Scott O'Connor , Zane D. Crawford , O. H. Ramachandran , John Luginsland , B. Shanker

We present the first experimental observation of modulation instability of partially spatially incoherent light beams in non-instantaneous nonlinear media. We show that even in such a nonlinear partially coherent system (of…

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