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Hydrodynamic instabilities driven by a direct current are analyzed in 2D and 3D relativisticlike systems with the Dyakonov-Shur boundary conditions supplemented by a boundary condition for temperature. Besides the conventional Dyakonov-Shur…

Mesoscale and Nanoscale Physics · Physics 2021-10-25 P. O. Sukhachov , E. V. Gorbar , I. A. Shovkovy

We derive an equation for energy transfer from relativistic charged particles to a cold background plasma appropriate for finite-size particles that are used in particle-in-cell simulation codes. Expressions for one-, two-, and…

Energy-based learning algorithms, such as predictive coding (PC), have garnered significant attention in the machine learning community due to their theoretical properties, such as local operations and biologically plausible mechanisms for…

Machine Learning · Computer Science 2024-10-08 Ankur Mali , Tommaso Salvatori , Alexander Ororbia

We study the hydrodynamical stability of the laminar flows associated with warped astrophysical discs using numerical simulations of warped shearing boxes. We recover linear growth rates reported previously due to a parametric resonance of…

Solar and Stellar Astrophysics · Physics 2018-12-19 Sijme-Jan Paardekooper , Gordon Ogilvie

This paper extends our recent results on multi-dimensional discrete-velocity models to the numerical level. By adopting an operator splitting scheme and introducing a suitable discrete Lyapunov function, we derive numerical control laws…

Numerical Analysis · Mathematics 2025-10-21 Haitian Yang , Wen-An Yong

Simulations of elastic turbulence, the chaotic flow of highly elastic and inertialess polymer solutions, are plagued by numerical difficulties: The chaotically advected polymer conformation tensor develops extremely large gradients and can…

Fluid Dynamics · Physics 2024-11-27 Sumithra R. Yerasi , Jason R. Picardo , Anupam Gupta , Dario Vincenzi

We study numerical methods for dissipative particle dynamics (DPD), which is a system of stochastic differential equations and a popular stochastic momentum-conserving thermostat for simulating complex hydrodynamic behavior at mesoscales.…

Numerical Analysis · Mathematics 2021-06-08 Xiaocheng Shang

Instabilities in 1D spatially extended systems are studied with the aid of both temporal and spatial Lyapunov exponents. A suitable representation of the spectra allows a compact description of all the possible disturbances in tangent…

chao-dyn · Physics 2009-10-28 Stefano Lepri , Antonio Politi , Alessandro Torcini

This paper discusses a novel fully implicit formulation for a 1D electrostatic particle-in-cell (PIC) plasma simulation approach. Unlike earlier implicit electrostatic PIC approaches (which are based on a linearized Vlasov-Poisson…

Computational Physics · Physics 2015-03-17 Guangye Chen , Luis Chacón , Daniel C. Barnes

QCD thermodynamics is considered using Wilson fermions in the fixed scale approach. The temperature dependence of the renormalized chiral condensate, quark number susceptibility and Polyakov loop is measured at four lattice spacings…

High Energy Physics - Lattice · Physics 2015-06-05 S. Borsanyi , S. Durr , Z. Fodor , C. Hoelbling , S. D. Katz , S. Krieg , D. Nogradi , B. C. Toth , N. Trombitas , K. K. Szabo

We have developed a method for extracting equilibrium observables from non-equilibrium simulations by rapidly changing the temperature and recording the subsequent evolution of the Polyakov loop. Both nucleation and spinodal decomposition…

High Energy Physics - Lattice · Physics 2007-05-23 Travis R. Miller , Michael C. Ogilvie

This paper proposes a charge-conserving, variational, spatio-temporal discretization for the drift-kinetic Vlasov-Maxwell system, utilizing finite-elements for the electromagnetic fields and the particle-in-cell approach for the Vlasov…

Plasma Physics · Physics 2019-10-09 Eero Hirvijoki

This work presents a structure-preserving, high-order, unconditionally stable numerical method for approximating the solution to the Fisher-Kolmogorov equation on polytopic meshes, with a particular focus on its application in simulating…

Numerical Analysis · Mathematics 2025-09-25 Paola F. Antonietti , Mattia Corti , Sergio Gómez , Ilaria Perugia

With the advent of PW class lasers, the very large laser intensities attainable on-target should enable the production of intense high order Doppler harmonics from relativistic laser-plasma mirrors interactions. At present, the modeling of…

Computational Physics · Physics 2017-10-11 G. Blaclard , H. Vincenti , R. Lehe , J. L. Vay

A conservative scheme has been formulated and verified for gyrokinetic particle simulations of electromagnetic waves and instabilities in magnetized plasmas. An electron continuity equation derived from drift kinetic equation is used to…

Plasma Physics · Physics 2018-03-14 J. Bao , Z. Lin , Z. X. Lu

An exponential time-integrator scheme of second-order accuracy based on the predictor-corrector methodology, denoted PCEXP, is developed to solve multi-dimensional nonlinear partial differential equations pertaining to fluid dynamics. The…

Computational Physics · Physics 2018-05-09 Shu-Jie Li , Li-Shi Luo , Z. J. Wang , Lili Ju

By comparing the impact of established laser smoothing techniques like Random Phase Plates (RPP) and Smoothing by Spectral Dispersion (SSD) to the concept of "Spike Trains of Uneven Duration and Delay" (STUD pulses) on the amplification of…

Plasma Physics · Physics 2015-06-11 Stefan Hüller , Bedros Afeyan

We study the statistics of first passage times (FPTs) of trajectory observables in both classical and quantum Markov processes. We consider specifically the FPTs of counting observables, that is, the times to reach a certain threshold of a…

Statistical Mechanics · Physics 2024-05-17 George Bakewell-Smith , Federico Girotti , Mădălin Guţă , Juan P. Garrahan

The instability of a Fermi-liquid drop with respect to bulk density distortions is considered. It is shown that the presence of the surface strongly reduces the growth rate of the bulk instability of the finite Fermi-liquid drop because of…

Nuclear Theory · Physics 2009-10-31 V. M. Kolomietz , S. Shlomo

We propose a continuous-time formulation of persistent contrastive divergence (PCD) for maximum likelihood estimation (MLE) of unnormalised densities. Our approach expresses PCD as a coupled, multiscale system of stochastic differential…

Machine Learning · Statistics 2025-10-03 Paul Felix Valsecchi Oliva , O. Deniz Akyildiz , Andrew Duncan