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In this note we continue our study of unidirectional solutions to hydrodynamic Euler alignment systems with strongly singular communication kernels $\phi(x):=|x|^{-(n+\alpha)}$ for $\alpha\in(0,2)$. The solutions describe unidirectional…

Analysis of PDEs · Mathematics 2020-02-17 Daniel Lear , Roman Shvydkoy

The kinetic theory of a self-gravitating system is considered in the framework of Bhatnager-Gross-Krook model. This approach offers a unique and tractable setup for studying the central, collision-dominated region of the system, as well as…

Statistical Mechanics · Physics 2007-05-23 A. E. Allahverdyan , Th. M. Nieuwenhuizen

The asymptotic analysis of kinetic models describing the behavior of particles interacting through alignment is performed. We will analyze the asymptotic regime corresponding to large alignment frequency where the alignment effects are…

Analysis of PDEs · Mathematics 2017-01-16 M. Bostan , J. A. Carrillo

We study hypocoercivity for a class of linear and linearized BGK models for discrete and continuous phase spaces. We develop methods for constructing entropy functionals that prove exponential rates of relaxation to equilibrium. Our…

Analysis of PDEs · Mathematics 2023-08-21 Franz Achleitner , Anton Arnold , Eric A. Carlen

We consider a kinetic model for a two component gas mixture without chemical reactions. Our goal is to study hypocoercivity for the linearized BGK model for gas mixtures in continuous phase space. By constructing an entropy functional, we…

Analysis of PDEs · Mathematics 2020-01-15 Liu Liu , Marlies Pirner

This letter studies the Euler-alignment system with weakly singular influence functions by introducing a novel technique to bound the density. Instead of resorting to a nonlinear maximum principle used in [C. Tan, Nonlinearity, 33:…

Analysis of PDEs · Mathematics 2021-10-22 Manas Bhatnagar , Hailiang Liu

We consider two distinguished asymptotic limits of the Euler equations in a gravitational field, namely the incompressible and Boussinesq limits. Both these limits can be obtained as singular limits of the Euler equations under appropriate…

Numerical Analysis · Mathematics 2019-02-04 K. R. Arun , S. Samantaray

We study spatially non-homogeneous kinetic models for vehicular traffic flow. Classical formulations, as for instance the BGK equation, lead to unconditionally unstable solutions in the congested regime of traffic. We address this issue by…

Physics and Society · Physics 2019-07-22 Michael Herty , Gabriella Puppo , Sebastiano Roncoroni , Giuseppe Visconti

In this short note we present the dynamics of a general scalar-tensor model, and in particular a scalar Einstein-Gauss-Bonnet model with a non-minimal coupling between gravity and the kinetic term of the scalar field. For the sake of…

General Relativity and Quantum Cosmology · Physics 2021-10-04 Fotis Fronimos

We introduce a structured approach to the construction of linear BGK-type collision operators ensuring that the resulting Lattice-Boltzmann methods are stable with respect to a weighted $L^2$-norm. The results hold for particular boundary…

Numerical Analysis · Mathematics 2020-02-07 Philipp Otte , Martin Frank

We consider the kinetic Cucker-Smale model with local alignment as a mesoscopic description for the flocking dynamics. The local alignment was first proposed by Karper, Mellet and Trivisa \cite{K-M-T-3}, as a singular limit of a normalized…

Analysis of PDEs · Mathematics 2018-09-13 Alessio Figalli , Moon-Jin Kang

Bhatnagar-Gross-Krook (BGK) equation is a relaxation model of the Boltzmann equation which is widely used in place of the Boltzmann equation for the simulation of various kinetic flow problems. In this work, we study the asymptotic…

Analysis of PDEs · Mathematics 2023-01-26 Gi-Chan Bae , Gyounghun Ko , Donghyun Lee , Seok-Bae Yun

This paper investigates the collisionless quantum hydrodynamic, or quantum Euler, system in \(\mathbb{T}^3\) with the linear pressure law \(P(\rho)=\rho\). Since this pressure is associated with the logarithmic internal energy…

Analysis of PDEs · Mathematics 2026-04-23 Cheng Yu

This paper is concerned with a modified entropy method to establish the large-time convergence towards the (unique) steady state, for kinetic Fokker-Planck equations with non-quadratic confinement potentials in whole space. We extend…

Analysis of PDEs · Mathematics 2024-01-23 Anton Arnold , Gayrat Toshpulatov

In this work, we propose a class of high order semi-Lagrangian scheme for a general consistent BGK model for inert gas mixtures. The proposed scheme not only fulfills indifferentiability principle, but also asymptotic preserving property,…

Numerical Analysis · Mathematics 2020-12-07 Seung Yeon Cho , Sebastiano Boscarino , Maria Groppi , Giovanni Russo

We consider the compressible Euler system with a family of nonlinear velocity alignments. The system is a nonlinear extension of the Euler-alignment system in collective dynamics. We show the asymptotic emergent phenomena of the system:…

Analysis of PDEs · Mathematics 2022-11-02 McKenzie Black , Changhui Tan

We present a general, high-order, fully explicit relaxation scheme which can be applied to any system of nonlinear hyperbolic conservation laws in multiple dimensions. The scheme consists of two steps. In a first (relaxation) step, the…

Numerical Analysis · Mathematics 2016-09-06 Pauline Lafitte , Ward Melis , Giovanni Samaey

In this paper we show, in a systematic way, how to relate the Kepler problem to the isotropic harmonic oscillator. Unlike previous approaches, our constructions are carried over in the Lagrangian formalism dealing with second order vector…

Mathematical Physics · Physics 2007-05-23 Antonella D'Avanzo , Giuseppe Marmo

We study a pressureless Euler system with a nonlinear density-dependent alignment term, originating in the Cucker-Smale swarming models. The alignment term is dissipative in the sense that it tends to equilibrate the velocities. Its density…

Analysis of PDEs · Mathematics 2017-11-22 Tam Do , Alexander Kiselev , Lenya Ryzhik , Changhui Tan

We study the quantum conformal gravity whose dynamics is governed by a single dimensionless gravitational coupling with negative beta function. Since the Euler term is not dynamical classically, the constant in front of it is not an…

High Energy Physics - Theory · Physics 2015-06-22 Ken-ji Hamada