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The particle-in-cell (PIC) method is successfully used to study magnetized plasmas. However, this requires large computational costs and limits simulations to short physical run-times and often to setups in less than three spatial…

High Energy Astrophysical Phenomena · Physics 2023-01-24 Rouven Lemmerz , Mohamad Shalaby , Timon Thomas , Christoph Pfrommer

In a mixed generalized linear model, the goal is to learn multiple signals from unlabeled observations: each sample comes from exactly one signal, but it is not known which one. We consider the prototypical problem of estimating two…

Statistics Theory · Mathematics 2026-01-12 Yihan Zhang , Marco Mondelli , Ramji Venkataramanan

We give a complete study of the asymptotic behavior of a simple model of alignment of unit vectors, both at the level of particles , which corresponds to a system of coupled differential equations, and at the continuum level, under the form…

Analysis of PDEs · Mathematics 2018-10-17 Amic Frouvelle , Jian-Guo Liu

The purpose of the present paper is to provide an overview of Asymptotic-Preserving methods for multiscale plasma simulations by addressing three singular perturbation problems. First, the quasi-neutral limit of fluid and kinetic models is…

Plasma Physics · Physics 2017-04-05 Pierre Degond , Fabrice Deluzet

In this paper, we consider a two-qubit system undergoing continuous-time measurements. In presence of multiple channels, we provide sufficient conditions on the continuous feedback control law ensuring almost sure exponential convergence to…

Optimization and Control · Mathematics 2019-03-19 Weichao Liang , Nina H. Amini , Paolo Mason

We study maximum-likelihood-type estimation for diffusion processes when the coefficients are nonrandom and observation occurs in nonsynchronous manner. The problem of nonsynchronous observations is important when we consider the analysis…

Statistics Theory · Mathematics 2022-07-04 Teppei Ogihara

The problem of the effect of two-frequency quasi-periodic perturbations on systems close to arbitrary nonlinear two-dimensional Hamiltonian ones is studied in the case when the corresponding perturbed autonomous systems have a double limit…

Dynamical Systems · Mathematics 2020-11-24 O. S. Kostromina

We propose a general mechanism for generating limit cycle (LC) oscillations by coupling a linear bosonic mode to a dissipative nonlinear bosonic mode. By analyzing the stability matrix, we show that LCs arise due to a supercritical Hopf…

If the primordial bispectrum is sufficiently large then the CMB hemispherical asymmetry may be explained by a large-scale mode of exceptional amplitude which perturbs the zeta two-point function. We extend previous calculations, which were…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-27 Christian T. Byrnes , Donough Regan , David Seery , Ewan R. M. Tarrant

This paper examines the temporal evolution of a two-stage stochastic model for spherical random fields. The model uses a time-fractional stochastic hyperbolic diffusion equation, which describes the evolution of spherical random fields on…

Spectral Theory · Mathematics 2024-12-10 Tareq Alodat , Quoc T. Le Gia

An algorithm is presented which generates pairs of oscillatory random time series which have identical periodograms but differ in the number of oscillations. This result indicate the intrinsic limitations of spectral methods when it comes…

Data Analysis, Statistics and Probability · Physics 2007-05-23 A. G. Rossberg

Symplectic tracking is important in accelerator beam dynamics simulation. So far, to the best of our knowledge, there is no self-consistent symplectic space-charge tracking model available in the accelerator community. In this paper, we…

Accelerator Physics · Physics 2017-02-01 Ji Qiang

This paper develops a two-stage stochastic model to investigate evolution of random fields on the unit sphere $\bS^2$ in $\R^3$. The model is defined by a time-fractional stochastic diffusion equation on $\bS^2$ governed by a diffusion…

Probability · Mathematics 2024-03-05 T. Alodat , Q. T. Le Gia , I. H. Sloan

We study the asymptotic dynamics of a driven spin-boson system where the environment is formed by a broadened localized mode. Upon exploiting an exact mapping, an equivalent formulation of the problem in terms of a quantum two-state system…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. C. Goorden , M. Thorwart , M. Grifoni

We present two dimensional (2D) particle-in-cell (PIC) simulations of 2D Bernstein-Greene-Kruskal (BGK) modes, which are exact nonlinear steady-state solutions of the Vlasov-Poisson equations, on a 2D plane perpendicular to a background…

Plasma Physics · Physics 2024-04-09 J. McClung , M. T. Franciscovich , K. Germaschewski , C. S. Ng

Owing to its numerical simplicity, a two-dimensional two-electron model atom, with each electron moving in one direction, is an ideal system to study non-perturbatively a fully correlated atom exposed to a laser field. Frequently made…

Atomic Physics · Physics 2009-10-30 D. Bauer

Periodically driven parametric oscillators offer a convenient way to simulate classical Ising spins. When many parametric oscillators are coupled dissipatively, they can be analogous to networks of Ising spins, forming an effective coherent…

We present a multimode treatment of the optical parametric oscillator, which is valid for both pulsed and continuous-wave pump fields. The two-time correlation functions of the output field are derived, and we apply the theory to analyze a…

Quantum Physics · Physics 2007-09-30 Anne E. B. Nielsen , Klaus Molmer

We consider optical response induced by bound states in the continuum (BICs) in arrays of dielectric spheres. By combining quasi-mode expansion technique with coupled mode theory (CMT) we put forward a theory of the optical response by…

Optics · Physics 2018-10-17 Evgeny N Bulgakov , Dmitrii N Maksimov

A fundamental task in particle-in-cell (PIC) simulations of plasma physics is solving for charged particle motion in electromagnetic fields. This problem is especially challenging when the plasma is strongly magnetized due to numerical…

Computational Physics · Physics 2026-01-01 Tri P. Nguyen , Ilon Joseph , Mayya Tokman