ATOMOSYD

2022 An atypical Lorenz-like system with an inversion symmetry

Letellier — 2026-06-13T06:21:12Z

In a study devoted to discrete Lorenz systems, Gonchenko and coworkers briefly mentioned a three-dimensional system that would be a Lorenz-like system if a quadratic monomial was not replaced with a cubic one. Such a modification introduces an in- version symmetry, rending this system atypical.
In 2022, Sergey Gonchenko and his collaborators proposed a Lorenz-like system with an inversion symmetry \(\Gamma_0\) combined with the common rotation symmetry \(\cal R_z^\pi\) around the (…)

- 3D flows

A possible procedure for extracting a template

Letellier — 2026-05-16T19:41:48Z

Defining the surface of section and computing the first-return map
To provide a non-trivial example for a template extraction, we will use the Lorenz system
\[\left\ \beginarrayl \displaystyle \dotx = - \sigma x + \sigma y \\[0.1cm] \doty = Rx - y - xz \\[0.1cm] \dotz = - bz + xy \, . \endarray \right.\] This system is equivariant under a rotation symmetry \(\cal R_z (\pi)\) that complexifies the state portrait. To simplify it, we modd (…)

- Algorithms

2026 La croissance exponentielle des petites erreurs

Letellier — 2026-05-14T06:54:37Z

Pièce chorégraphique avec la Cie Kashyl

- Scientific Mediations

2025

Letellier — 2026-05-02T08:05:06Z

Ludovico Minati, Vitrice Ruben Folifack Signing, Léandre Kamdjeu Kengne, Manyu Zhao, Pedro Antonio Valdes-Sosa, Hiroyuki Ito, Xu Zhang, Leonardo Ricci & Christophe Letellier A three-dimensional non-autonomous conservative chaotic system based on cross-phase-coupled oscillators : Theoretical analysis and electronic realization Chaos, Solitons & Fractals, 200, 116877, 2025. Online Abstract This study concerns a conservative, non-autonomous chaotic system composed of three ordinary (…)

- Papers

2024

Letellier — 2026-05-02T08:01:19Z

Caterina Mosto, Gisela D. Charó, Christophe Letellier & Denisse Sciamarella Templex-based dynamical units for a taxonomy of chaos Chaos, 34, 113111, 2024 [Online] Abstract Discriminating different types of chaos is still a very challenging topic, even for dissipative three-dimensional systems for which the most advanced tool is the template. Nevertheless, getting a template is, by definition, limited to three-dimensional objects based on knot theory. To deal with higher-dimensional (…)

- Papers

2023

Letellier — 2026-05-02T07:41:42Z

Christophe Letellier, Sylvain Mangiarotti, Ludovico Minati, Mattia Frasca & Jean-Pierre Barbot Optimal placement of sensor and actuator for controlling low-dimensional chaotic systems based on global modeling Chaos, 33, 013140, 2023 Online] Abstract Controlling chaos is fundamental in many applications, and for this reason, many techniques have been proposed to address this problem. Here, we propose a strategy based on an optimal placement of the sensor and actuator providing global (…)

- Papers

2026

Letellier — 2026-04-24T05:12:25Z

I. Leyva, I. Sendiña-Nadal, R. Sevilla-Escoboza, V. P. Vera-Ávila & C. Letellier From chaotic itinerancy to intermittent synchronization in complex networks Physical Review Research, 8, 013328, 2026. Online Abstract Although synchronization has been extensively studied, key processes underlying its emergence in complex networks have remained hidden by the use of global order parameters. Here, we uncover how the route to synchronization unfolds through a sequential transition between two (…)

- Papers

Recollections from the Early Days of Chaos Theory (2026)

Letellier — 2026-04-23T04:36:39Z

This book is both a historical document and a tribute to the people behind the equations — a unique opportunity to witness the birth of chaos theory through the eyes of those who lived it.

- Books

1995 A Wien-bridge oscillator

Letellier — 2022-05-01T17:50:05Z

In the 1980s, many electronic circuits producing chaotic regimes were proposed. Most of the proposed circuits are modifications of a LC circuit which is not convenient to produce audio and lower frequencies. The RC circuits are more acceptable for low frequencies but they are often rather complex. A. Namajhas and Arunas Tamasevicius proposed a simple electronic circuit made of a Wien bridge, a single opamp and a single nonlinear device displaying a current saturation characteristic . The (…)

- Chaos in electronic circuits

Introduction à la circulation des fluides physiologiques (2022)

Letellier — 2022-04-21T09:09:46Z

3ème édition parue le 27 Septembre 2022
Les fluides physiologiques servent au transport de molécules impliquées dans le fonctionnement des grands organismes, des nutriments, de l'oxygène, etc. Par exemple, l'air est apporté aux poumons par la ventilation, le sang diffuse l'oxygène jusqu'aux muscles et extrait les "déchets" comme le dioxyde de carbone pour les éliminer du corps. Ce livre se présente comme une introduction à la mécanique des fluides nécessaire à une première approche de la (…)

- Books