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A consistent guiding-center Hamiltonian theory is derived by Lie-transform perturbation method, with terms up to second order in magnetic-field nonuniformity. Consistency is demonstrated by showing that the guiding-center transformation…

Plasma Physics · Physics 2015-12-09 Natalia Tronko , Alain Brizard

This paper develops the theory of affine Euler-Poincar\'e and affine Lie-Poisson reductions and applies these processes to various examples of complex fluids, including Yang-Mills and Hall magnetohydrodynamics for fluids and superfluids,…

Mathematical Physics · Physics 2009-03-26 François Gay-Balmaz , Tudor S. Ratiu

We provide convergence guarantees in Wasserstein distance for a variety of variance-reduction methods: SAGA Langevin diffusion, SVRG Langevin diffusion and control-variate underdamped Langevin diffusion. We analyze these methods under a…

Machine Learning · Statistics 2018-02-16 Niladri S. Chatterji , Nicolas Flammarion , Yi-An Ma , Peter L. Bartlett , Michael I. Jordan

This work provides a rigorous and self-contained introduction to numerical methods for Hamiltonian simulation in quantum computing, with a focus on high-order product formulas for efficiently approximating the time evolution of quantum…

Quantum Physics · Physics 2025-07-16 Javier Lopez-Cerezo

The Landau-Lifshitz equation is derived as the reduction of a geodesic flow on the group of maps into the rotation group. Passing the symmetries of spatial isotropy to the reduced space is an example of semidirect product reduction by…

Symplectic Geometry · Mathematics 2007-05-23 G. W. Patrick

Blood flow in arterial systems can be described by the three-dimensional Navier-Stokes equations within a time-dependent spatial domain that accounts for the elasticity of the arterial walls. In this article blood is treated as an…

Numerical Analysis · Mathematics 2018-08-14 Francesco Fambri , Michael Dumbser , Vincenzo Casulli

Reduction theory has played a major role in the study of Hamiltonian systems. On the other hand, the Hamilton-Jacobi theory is one of the main tools to integrate the dynamics of certain Hamiltonian problems and a topic of research on its…

Mathematical Physics · Physics 2015-09-02 Manuel de León , David Martín de Diego , Miguel Vaquero

Let $\mathbb{H}$ be the sub-Riemannian Heisenberg group. That $\mathbb{H}$ supports a rich family of quasiconformal mappings was demonstrated by Kor\'{a}nyi and Reimann using the so-called flow method. Here we supply further evidence of the…

Classical Analysis and ODEs · Mathematics 2020-01-31 Alex D. Austin

This paper develops the theory of Dirac reduction by symmetry for nonholonomic systems on Lie groups with broken symmetry. The reduction is carried out for the Dirac structures, as well as for the associated Lagrange-Dirac and…

Symplectic Geometry · Mathematics 2014-10-21 François Gay-Balmaz , Hiroaki Yoshimura

The investigation of symmetries of b-symplectic manifolds and folded-symplectic manifolds is well-understood when the group under consideration is a torus (see, for instance, [GMPS,GLPR, GMW18a] for b-symplectic manifolds and [CGP, CM] for…

Symplectic Geometry · Mathematics 2023-06-27 Anastasia Matveeva , Eva Miranda

This paper deals with the Lagrangian analogue of symplectic or point reduction by stages. We develop Routh reduction as a reduction technique that preserves the Lagrangian nature of the dynamics. To do so we heavily rely on the relation…

Mathematical Physics · Physics 2011-11-30 Bavo Langerock , Tom Mestdag , Joris Vankerschaver

When expressed in Lagrangian variables, the equations of motion for compressible (barotropic) fluids have the structure of a classical Hamiltonian system in which the potential energy is given by the internal energy of the fluid. The…

Analysis of PDEs · Mathematics 2021-12-21 Thomas Gallouët , Quentin Merigot , Andrea Natale

We describe the reduction procedure for a symplectic Lie algebroid by a Lie subalgebroid and a symmetry Lie group. Moreover, given an invariant Hamiltonian function we obtain the corresponding reduced Hamiltonian dynamics. Several examples…

Differential Geometry · Mathematics 2008-04-24 D. Iglesias , J. C. Marrero , D. Martin de Diego , E. Martinez , E. Padron

The theory of flows was used as a crucial tool in the recent proof by Margolis, Rhodes and Schilling that Krohn-Rhodes complexity is decidable. In this paper we begin a systematic study of aperiodic flows. We give the foundations of the…

Dynamical Systems · Mathematics 2025-02-04 Stuart Margolis , John Rhodes

Motivated by the notion of Lagrangian multiforms, which provide a Lagrangian formulation of integrability, and by results of the authors on the role of covariant Hamiltonian formalism for integrable field theories, we propose the notion of…

Mathematical Physics · Physics 2020-12-29 Vincent Caudrelier , Matteo Stoppato

We study certain symplectic quotients of n-fold products of complex projective m-space by the unitary group acting diagonally. After studying nonemptiness and smoothness these quotients we construct the action-angle variables, defined on an…

Symplectic Geometry · Mathematics 2007-05-23 Hermann Flaschka , John Millson

We propose a generalization of the reduction of Poisson manifolds by distributions introduced by Marsden and Ratiu. Our proposal overcomes some of the restrictions of the original procedure, and makes the reduced Poisson structure…

Symplectic Geometry · Mathematics 2009-05-29 Fernando Falceto , Marco Zambon

Studying high-dimensional Hamiltonian systems with microstructure, it is an important and challenging problem to identify reduced macroscopic models that describe some effective dynamics on large spatial and temporal scales. This paper…

Mathematical Physics · Physics 2008-12-27 Johannes Giannoulis , Michael Herrmann , Alexander Mielke

We present a new existence mechanism, based on symplectic topology, for orbits of Hamiltonian flows connecting a pair of disjoint subsets in the phase space. The method involves function theory on symplectic manifolds combined with rigidity…

Symplectic Geometry · Mathematics 2021-01-12 Michael Entov , Leonid Polterovich

A simple application of the semipositivity.

Algebraic Geometry · Mathematics 2007-05-23 Yujiro Kawamata