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We present the capability of Lagrangian descriptors for revealing the high dimensional phase space structures that are of interest in nonlinear Hamiltonian systems with index-1 saddle. These phase space structures include normally…

Dynamical Systems · Mathematics 2019-08-14 Shibabrat Naik , Stephen Wiggins

In this paper we apply the method of Lagrangian descriptors to explore the geometrical structures in phase space that govern the dynamics of dissipative systems. We demonstrate through many classical examples taken from the nonlinear…

Dynamical Systems · Mathematics 2021-10-04 V. J. García-Garrido , J. García-Luengo

In this paper we demonstrate the capability of the method of Lagrangian descriptors to unveil the phase space structures that characterize transport in high-dimensional symplectic maps. In order to illustrate its use, we apply it to a…

Chaotic Dynamics · Physics 2021-11-24 M. Agaoglou , V. J. Garcia-Garrido , M. Katsanikas , S. Wiggins

In this article we present the influence of a Hamiltonian saddle-node bifurcation on the high-dimensional phase space structures that mediate reaction dynamics. To achieve this goal, we identify the phase space invariant manifolds using…

Chaotic Dynamics · Physics 2020-05-20 Víctor J. García-Garrido , Shibabrat Naik , Stephen Wiggins

In this paper we explore the phase space structures governing isomerization dynamics on a potential energy surface with four wells and an index-2 saddle. For this model, we analyze the influence that coupling both degrees of freedom of the…

Chaotic Dynamics · Physics 2020-06-24 Víctor J. García-Garrido , Makrina Agaoglou , Stephen Wiggins

In this paper we develop new techniques for revealing geometrical structures in phase space that are valid for aperiodically time dependent dynamical systems, which we refer to as Lagrangian descriptors. These quantities are based on the…

Chaotic Dynamics · Physics 2013-08-05 Ana M. Mancho , Stephen Wiggins , Jezabel Curbelo , Carolina Mendoza

We study the phase space geometry associated with index 2 saddles of a potential energy surface and its influence on reaction dynamics for $n$ degree-of-freedom (DoF) Hamiltonian systems. For index 1 saddles of potential energy surfaces…

Chaotic Dynamics · Physics 2015-05-13 Gregory S. Ezra , Stephen Wiggins

Hamiltonian dynamical systems possessing equilibria of ${saddle} \times {centre} \times...\times {centre}$ stability type display \emph{reaction-type dynamics} for energies close to the energy of such equilibria; entrance and exit from…

Chaotic Dynamics · Physics 2015-05-13 Holger Waalkens , Stephen Wiggins

We propose Lagrangian Descriptors (LDs) as a diagnostic framework for evaluating neural network models of Hamiltonian systems beyond conventional trajectory-based metrics. Standard error measures quantify short-term predictive accuracy but…

Machine Learning · Computer Science 2026-04-02 Abrari Noor Hasmi , Haralampos Hatzikirou , Hadi Susanto

Reaction rates of chemical reactions under nonequilibrium conditions can be determined through the construction of the normally hyperbolic invariant manifold (NHIM) [and moving dividing surface (DS)] associated with the transition state…

Chemical reactions in multidimensional driven systems are typically described by a time-dependent rank-1 saddle associated with one reaction and several orthogonal coordinates (including the solvent bath). To investigate reactions in such…

Chemical Physics · Physics 2020-02-06 Matthias Feldmaier , Robin Bardakcioglu , Johannes Reiff , Jörg Main , Rigoberto Hernandez

In this article, we review the analytical and numerical approaches for computing the phase space structures in two degrees-of-freedom Hamiltonian systems that arise in chemical reactions. In particular, these phase space structures are the…

Chaotic Dynamics · Physics 2020-04-14 Wenyang Lyu , Shibabrat Naik , Stephen Wiggins

The goal of this paper is to apply the method of Lagrangian descriptors to reveal the phase space mechanism by which a Caldera-type potential energy surface (PES) exhibits the dynamical matching phenomenon. Using this technique, we can…

Chaotic Dynamics · Physics 2020-11-30 M. Katsanikas , Víctor J. García-Garrido , S. Wiggins

We consider the existence of invariant manifolds in phase space governing reaction dynamics in situations where there are no saddle points on the potential energy surface in the relevant regions of configuration space. We point out that…

Chemical Physics · Physics 2010-11-04 Gregory S. Ezra , Stephen Wiggins

A computational procedure that allows the detection of a new type of high-dimensional chaotic saddle in Hamiltonian systems with three degrees of freedom is presented. The chaotic saddle is associated with a so-called normally hyperbolic…

Chaotic Dynamics · Physics 2009-11-10 H. Waalkens , A. Burbanks , S. Wiggins

This paper provides a theoretical background for Lagrangian Descriptors (LDs). The goal of achieving rigourous proofs that justify the ability of LDs to detect invariant manifolds is simplified by introducing an alternative definition for…

We develop the geometrical, analytical, and computational framework for reactive island theory for three degrees-of-freedom time-independent Hamiltonian systems. In this setting, the dynamics occurs in a 5-dimensional energy surface in…

Chaotic Dynamics · Physics 2021-07-14 Vladimír Krajňák , Víctor J. García-Garrido , Stephen Wiggins

We used for the first time the method of periodic orbit dividing surfaces in a non-integrable Hamiltonian system with three degrees of freedom. We have studied the structure of these four dimensional objects in the five dimensional phase…

Chaotic Dynamics · Physics 2022-05-11 Matthaios Katsanikas , Stephen Wiggins

Eulerian and Lagrangian tools are used to detect coherent structures in the velocity and magnetic fields of a mean--field dynamo, produced by direct numerical simulations of the three--dimensional compressible magnetohydrodynamic equations…

Solar and Stellar Astrophysics · Physics 2013-11-21 Erico L. Rempel , Abraham C. -L. Chian , Axel Brandenburg , Pablo R. Muñoz

We study geometry of the phase space for finite-dimensional dynamical systems with degenerate Lagrangians. The Lagrangian and Hamiltonian constraint formalisms are treated as different local-coordinate pictures of the same invariant…

Mathematical Physics · Physics 2007-05-23 Vladimir Pavlov , Andrei Starinets
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