Christophe Letellier

Last news: Launch of my WebTV Héritages Scientifiques

Friday December 10, 2020

Here

Ph.D. Thesis (DOI: 10.13140/RG.2.1.1280.5281)

I was born in 1966. I received a Bachelor degree in 1985. From 1985 to June 1989, I was involved in Physics. As a result of this work, in 1989, I received a Master’s degree in Physics from University of Rouen. In September 1990, I was involved in the DEA Champs, Particules, Matières (University of Orsay). In September 1991, I joined the CORIA as a research student for working on Topological characterization and global modelling of chaotic attractors. In May 1994, I received a Ph.D. degree for these researches.

Habilitation (1998)

In September 1994, I joined the Department of Physics of the University of Rouen as a temporary assistant professor where I got a permanent position in September 1996. I got my Habilitation to Direct Researches in January 1998 and became full professor in 2007.

From June 2006 to December 2013, I was the head of GdR 2984 DYCOEC (Dynamics and Control of Complex Sets).

I regularly serve as a referee to various Scientific Journals (Physical Review Letters, Physical Review E, Journal of Physics A, Chaos, European Journal of Physics, Journal of Theoretical Biology, International Journal of Bifurcations & Chaos, Journal of Fluid Mechanics...). I am a PLOS One Editorial member.

 ORCID account

 TEACHING

Currently, I am lecturing for undergraduate students (fluid mechanics for students in the first year of the medical course) and to Master students (nonlinear dynamical systems theory, Introduction to Fluid dynamics and boundary layers). In the past, I taught history of science, introduction to astrophysics, introduction to atomic and nuclear physics, ntroduction to mechanics... I supervised Master projects as well as post-graduate researches in the theory of non Linear Dynamical Systems (from theory to biomedical applications). From 2008 to 2015, I was in charge to manage a course in Engineering for Bio-Medicine (IBIOM). I taught

• History of Science (epistemology and astronomy)
• Basic Mechanics
• Fluid Mechanics (Navier-Stokes equations and physiological fluids)
• Introduction to Modern Physics (atomic and nuclear physics)
• Nonlinear Biomedical dynamics (Chaos theory and biomedical applications)

 Research

My main research topics include :

• Topological characterization of chaotic attractors (with Robert Gilmore)

• Equivariant dynamical systems

• Global modelling from a single scalar time series (with Luis A. Aguirre, Sylvain Mangiarotti and Claudia Lainscsek)

• Observability of dynamical systems (with Luis A. Aguirre, Jean-Pierre Barbot, Ezequiel Bianco-Martinez, Murilo Baptista and Irene Sendina-Nadal).

• Controllability and Flatness with Jean-Pierre Barbot and Luis A. Aguirre

• Analysis of data from the real worl using tools borrowed from the nonlinear dynamical systems theory.
  • Variability in the cardio-respiratory system (breathing patterns, heart variability)
  • Synchronization between patient ventilatory cycles and machine pressure cycles in noninvasive mechanical ventilation
  • Sleep scoring and quality from polysomnographic data (with Valérie Messager
  • Dynamics of mediated interactions
  • Modelling of tumor growth and follow-up of patients who have been treated for cancer (with Dr Fabrice Denis)

• History of Science
  • Kepler’s astronomy
  • Early atomic models
  • Poincaré’s contribution to special relativity (with Valérie Messager)
  • Mass-energy equivalence
  • Chaos theory with a special attention to Otto Rössler’s contribution: I edited a book he wrote in the 1980’s but that he never published... It was rencently published by Springer.

 Publications

• I wrote five books
  • 2006: one in French entitled Le chaos dans la nature published by Vuibert
  • 2007: one in English with Robert Gilmore and entitled The symmetry of Chaos, published by Oxford University Press
  • 2011: one in French entitled Introduction à la circulation des fluides physiologiques published by Ellipses with a third edition published in 2022
  • 2019 one in English entitled Chaos in nature:This is the second edition.
  • 2020: one in English entitled Chaos: the world of nonperiodic solutions. This is a book written by Otto E. Rössler in the early 1980s and which was never published before. Three appendices were inserted to this book.

• Papers
  • Most published works concern topological analysis of equivariant systems and global modelling from experimental data (in collaboration with many groups who collected the data) and biomedical applications
  • More details in PUBLICATIONS

 Web TV

• On December 10, 2020, I launched my channel Héritages Scientifiques on the Web TV from the Rouen Normandie University. It is devoted to some of my talks about chaos theory, history of science, biomedical applicatoins...

• Le chaos : du problème des trois corps au cancer
  Rouen University on February 5, 2015

• Cieux chaotiques : de la théorie de la lune à l’activité solaire
  Streamed live on March 23, 2016.

• Systèmes dynamiques chaotiques: des concepts aux applications Observatoire Midi-Pyrénées, Toulouse, 22 Septembre 2020

• Edward Lorenz et la théorie du chaos (Ecole Polytechnique, 10 Décembre 2020)

• Taxonomy of chaos: towards a classification of chaotic attractors (SIAM Conference on Applications of Dynamical Systems, May 27, 2021)

 Scientific mediations

• See Scientific Mediations
• La théorie du chaos fête ses 130 ans

 Hobbies

• I like travelling in the world with a preference for the non globalized countries... You may consult some pictures from my trip in India (1991 and 1992) on this site : Koakidi. India was the first country outside from Europe I ever visited: I was touched by the atmosphere in this country which remains one of my prefered destination.

• I am playing jazz piano. Thelonious Monk is definitely my prefered Jazz pianist but I like also the "singing melodies" played by Wynton Kelly.

• I am practicing almost daily biking or indoor and on-water rowing.

  

 Jazz Today, I am listening Smart Set by Mourad Benhammou and his jazz workers. Mourad is now a quite reputed French drummer and, also, a friend for 30 years... He plays in this CD with some young French cats (Fabien Marcoz, Pierre Christophe, Fabien Mary and David Sauzay. A jazz coming from the 60’s with a young touch.

A tribute to Roland Kirk by Mourad and his friends.

With the Raphaël Imbert Quartet on France Musique

A tribute to Hank Jones : sur TSF Jazz

and Abbey sings Abbey by Abbey Lincoln, a great emotive Jazz voice... who is now a small star in the sky.

Among the new CDs in my collection, one is entitled Burning Bright played by the very amazing pianist, Tom McClung who enjoys quoting Duke Ellington, Thelonious Monk, McCoy Tyner, Horace Parlan (among others) to enrich his own musical universe. A very open and touchy music with an obvious sense of humor produced with Matyas Szandaï and Mourad Benhammou. Highly recommended.

Victor Hugo

Nous sommes dans une période particulièrement sombre où la société est plus gouvernée par la peur que par la raison. Citons ce passage des travailleurs de la mer de Victor Hugo:

Les superstitieux font des signes de crois et non des procès-verbaux. Ils voient ou croient voir, s’enfuient et se taisent. Il existe une connivence tacite, non voulue, mais réelle, entre ceux qui font peur et ceux qui ont peur. Les effrayés se sentent dans leur tort d’avoir été effrayés, ils s’imaginent avoir surpris un secret, ils craignent d’aggraver leur position, mystérieuse pour eux-mêmes, et de faĉher les apparitions. Ceci les rend discrets. Et, même en dehors de ce calcul, l’instinct des gens crédules est le silence ; il y a du mutisme dans l’épouvante ; les terrifiés parlent peu ; il semble que l’horreur dise : chut !

George Orwell, Essais, articles, lettres:

Utiliser avec discernement les produits de la science et de l’industrie, en leur appliquant à tous le même critère : cela me rend-il plus humain ou moins humain ?

Günther Anders, L’Obsolescence de l’homme, 1956

Günther Anders

L’idéal serait de formater les individus dès la naissance en limitant leurs aptitudes biologiques innées. Ensuite, on poursuivrait le conditionnement en réduisant de manière drastique l’éducation, pour la ramener à une forme d’insertion professionnelle. Un individu inculte n’a qu’un horizon de pensée limité et plus sa pensée est bornée à des préoccupations médiocres, moins il peut se révolter. Il faut faire en sorte que l’accès au savoir devienne de plus en plus difficile et élitiste. Que le fossé se creuse entre le peuple et la science, que l’information destinée au grand public soit anesthésiée de tout contenu à caractère subversif.

Surtout pas de philosophie. Là encore, il faut user de persuasion et non de violence directe : on diffusera massivement, via la télévision, des divertissements flattant toujours l’émotionnel ou l’instinctif. On occupera les esprits avec ce qui est futile et ludique. Il est bon, dans un bavardage et une musique incessante, d’empêcher l’esprit de penser. On mettra la sexualité au premier rang des intérêts humains. Comme tranquillisant social, il n’y a rien de mieux.

En général, on fera en sorte de bannir le sérieux de l’existence, de tourner en dérision tout ce qui a une valeur élevée, d’entretenir une constante apologie de la légèreté ; de sorte que l’euphorie de la publicité devienne le standard du bonheur humain et le modèle de la liberté. Le conditionnement produira ainsi de lui-même une telle intégration, que la seule peur – qu’il faudra entretenir – sera celle d’être exclus du système et donc de ne plus pouvoir accéder aux conditions nécessaires au bonheur.

L’homme de masse, ainsi produit, doit être traité comme ce qu’il est : un veau, et il doit être surveillé comme doit l’être un troupeau. Tout ce qui permet d’endormir sa lucidité est bon socialement, ce qui menacerait de l’éveiller doit être ridiculisé, étouffé, combattu. Toute doctrine mettant en cause le système doit d’abord être désignée comme subversive et terroriste et ceux qui la soutiennent devront ensuite être traités comme tels.