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We develop a mesh-based semi-Lagrangian discretization of the time-dependent incompressible Navier-Stokes equations with free boundary conditions recast as a non-linear transport problem for a momentum 1-form. A linearly implicit fully…

Numerical Analysis · Mathematics 2024-02-05 Wouter Tonnon , Ralf Hiptmair

We consider $n$-dimensional asymptotically anti-de Sitter spacetimes in higher curvature gravitational theories with $n \geq 4$, by employing the conformal completion technique. We first argue that a condition on the Ricci tensor should be…

High Energy Physics - Theory · Physics 2009-11-11 Naoya Okuyama , Jun-ichirou Koga

Quaternions have an (over a century-old) extensive and quite complicated interaction with special relativity. Since quaternions are intrinsically 4-dimensional, and do such a good job of handling 3-dimensional rotations, the hope has always…

General Relativity and Quantum Cosmology · Physics 2020-03-16 Thomas Berry , Matt Visser

We derive third order transport coefficients of skewness for a phase-space kinetic model that considers the processes of scattering collisions, trapping, detrapping and recombination losses. The resulting expression for the skewness tensor…

Statistical Mechanics · Physics 2017-09-26 Peter W. Stokes , Ilija Simonović , Bronson Philippa , Daniel Cocks , Saša Dujko , Ronald D. White

A covariant - tensor method for $SU(2)_{q}$ is described. This tensor method is used to calculate q - deformed Clebsch - Gordan coefficients. The connection with covariant oscillators and irreducible tensor operators is established. This…

High Energy Physics - Theory · Physics 2009-10-22 Stjepan Meljanac , Marijan Milekovic

We propose a novel second-order ODE as the continuous-time limit of a Riemannian accelerated gradient-based method on a manifold with curvature bounded from below. This ODE can be seen as a generalization of the ODE derived for Euclidean…

Optimization and Control · Mathematics 2020-03-10 Foivos Alimisis , Antonio Orvieto , Gary Bécigneul , Aurelien Lucchi

A recently proposed theory of modified gravity with an explicit ``anomalous'' coupling of the Ricci curvature to matter is discussed, and an inequality is derived which expresses a necessary and sufficient condition to avoid the notorius…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Valerio Faraoni

Besides black holes, the phase space of three-dimensional massive gravity about Warped-Anti de Sitter (WAdS) space contains solutions that decay exponentially in time. They describe evanescent graviton configurations that, while governed by…

High Energy Physics - Theory · Physics 2016-01-13 Gaston Giribet , Yerko Vasquez

By employing a Chapman-Enskog like iterative solution of the Boltzmann equation in relaxation-time approximation, we derive a new expression for the entropy four-current up to third order in gradient expansion. We show that unlike…

Nuclear Theory · Physics 2015-03-02 Chandrodoy Chattopadhyay , Amaresh Jaiswal , Subrata Pal , Radoslaw Ryblewski

Topological order is a new type order that beyond Landau's symmetry breaking theory. It has some interesting properties, such as producing quasi-particles with fractional quantum numbers and fractional/Fermi statistics, robust gapless…

High Energy Physics - Theory · Physics 2021-12-03 JIngbo Wang

We investigate local and global strong solutions for the incompressible viscoelastic system of Oldroyd--B type. We obtain the existence and uniqueness of a solution in a functional setting invariant by the scaling of the associated…

Analysis of PDEs · Mathematics 2011-02-01 Ting Zhang , Daoyuan Fang

We consider a degenerate quasilinear chemotaxis--Stokes type involving rotation in the aggregative term, \begin{equation} \left\{ \begin{array}{l} n_t+u\cdot\nabla n=\Delta n^m-\nabla\cdot(nS(x,n,c)\cdot\nabla c),\quad x\in \Omega, t>0,…

Analysis of PDEs · Mathematics 2017-01-06 Jiashan Zheng

Tensor analysis provides a frame-invariant foundation for continuum mechanics, yet numerical implementations rely on matrix representations expressed in user-selected bases. When these bases are non-Cartesian and non-orthonormal, additional…

Numerical Analysis · Mathematics 2026-03-10 Giuliano Pretti , Robert E. Bird , William M. Coombs , Charles E. Augarde

This paper concerns the construction of traveling wave solutions to the free boundary incompressible Navier-Stokes system. We study a single layer of viscous fluid in a strip-like domain that is bounded below by a flat rigid surface and…

Analysis of PDEs · Mathematics 2022-09-13 Junichi Koganemaru , Ian Tice

We construct an invariant for non-spin 4-manifolds by using 2-torsion cohomology classes of moduli spaces of instantons on SO(3)-bundles. The invariant is an SO(3)-version of Fintushel-Stern's 2-torsion instanton invariant. We show that…

Geometric Topology · Mathematics 2007-05-23 H. Sasahira

A novel tensor decomposition framework, termed Tensor Star (TS) decomposition, is proposed which represents a new type of tensor network decomposition based on tensor contractions. This is achieved by connecting the core tensors in a ring…

Image and Video Processing · Electrical Eng. & Systems 2024-09-10 Wuyang Zhou , Yu-Bang Zheng , Qibin Zhao , Danilo Mandic

We prove (without exceptions) the existence of irredundant tensor decompositions with the number of addenda equal to rank $+1$. We also discuss the existence of decompositions with more than the tensor rank terms, which are concise, while…

Algebraic Geometry · Mathematics 2020-02-17 Edoardo Ballico

We propose a linearized semi-implicit and decoupled finite element method for the incompressible Navier--Stokes equations with variable density. Our method is fully discrete and shown to be unconditionally stable. The velocity equation is…

Numerical Analysis · Mathematics 2021-12-28 Buyang Li , Weifeng Qiu , ZongZe Yang

We derive a new formulation of the $3D$ compressible Euler equations with dynamic entropy exhibiting remarkable null structures and regularity properties. Our results hold for an arbitrary equation of state (which yields the pressure in…

Analysis of PDEs · Mathematics 2017-01-25 Jared Speck

We introduce a scalar invariant on manifolds with density which is analogous to the renormalized volume coefficient $v_3$ in conformal geometry. We show that this invariant is variational and that shrinking gradient Ricci solitons are…

Differential Geometry · Mathematics 2016-03-10 Jeffrey S. Case