• since 2003 : CNRS researcher (CR1), Centre de Physique Théorique
• 2001-2002: Joseph Ford Fellow at the Center for Nonlinear Science , Georgia Institute of Technology
• 2000: Postdoctoral Fellow at the Service de Physique Théorique, CEA Saclay
• 1997-1999: Teaching Assistant at the University of Dijon

• Habilitation à Diriger les Recherches (2006), Université Aix-Marseille II
• Ph.D. (1999), University of Dijon
• graduated from the Ecole Normale Supérieure de Lyon (1993-1997)

• expert/evaluator in the FP7 of the European Community and for the EACEA
• Associate Editor of Communications in Nonlinear Science and Numerical Simulation
• member of the Carnot Foundation
• local scientific coordinator of the ANR network EGYPT
• coordinator of PICS-CNRS program (#4173) with the Center for Nonlinear Science - Georgia Tech
• referee for Cent. Eur. J. Phys., Chaos, CNSNS, DCDS-A, DCDS-B, Eur. Phys. J. B, Europhys. Lett., Int. J. Appl. Math. Stat., J. Math. Imag. Vis. , J. Phys. A: Math. Gen., J. Sound Vibr., Mech. Res. Commun., Nonlinearity, Nucl. Fusion, Physica D , Phys. Rev. E , Phys. Scr. , Phys. Rev. Lett. , Phys. Lett. A, Phys. Fluids, Phys. Plasmas , Plasma Phys. Contr. Fusion
• reviewer for Mathematical Reviews, NSF proposals

Strong field double ionization

    One of the most striking surprises of recent years in intense laser-matter interactions has come from multiple ionization by intense short laser pulses: Correlated (nonsequential) double ionization rates were found to be several orders of magnitude higher than the uncorrelated sequential
mechanism allows. This discrepancy has made the characteristic ‘‘knee’’ shape in the double ionization yield versus intensity plot into one of the most dramatic manifestations of electron-electron correlation in nature. We investigate the nonlinear dynamics of these systems and relate the qualitative changes observed in the double ionization probability versus intensity plots to phase space structures and their bifurcations. In this way, we identify the phase space structures that regulate atomic double ionization in strong ultrashort laser pulses.    

Control of Hamiltonian chaos

    Controlling chaotic transport is a key challenge in many branches of physics like particle accelerator physics, free electron lasers or magnetically confined fusion plasmas. One way to control transport would be that of reducing or suppressing chaos. Most of the methods for controlling chaotic systems is done by tilting targeted trajectories. However, for many body experiments like the magnetic confinement of a plasma or the control of turbulent flows, such methods are hopeless due to the high number of trajectories to deal with simultaneously. For these systems, it is desirable to control transport properties without significantly altering the original system under investigation nor its overall chaotic structure. Here we focus on a different strategy which aims at modifying the phase space structures by adding a small apt perturbation or by tuning appropriately the parameters. 

Renormalization for the analysis of stability in Hamiltonian flows
(abstract of Physics Reports, vol. 365, Issue 1, 2002)

    We study the stability of Hamiltonian systems in classical mechanics with two degrees of freedom by renormalization-group methods. One of the key mechanisms of the transition to chaos is the break-up of invariant tori, which plays an essential role in the large scale and long term behavior. The aim is to determine the threshold of break-up of invariant tori and its mechanism.  The idea is to construct a renormalization transformation as a canonical change of coordinates, which deals with the dominant resonances leading to qualitative changes in the dynamics. Numerical results show that this transformation is an efficient tool for the determination of the threshold of the break-up of invariant tori for Hamiltonian systems with two degrees of freedom. The analysis of this transformation indicates that the break-up of invariant tori is a universal mechanism. The properties of invariant tori are described by the renormalization flow. A trivial attractive set of the renormalization transformation characterizes the Hamiltonians that have a smooth invariant torus. The set of Hamiltonians that have a non-smooth invariant torus is a fractal surface. This critical surface is the stable manifold of a single strange set encompassing all irrational frequencies. This hyperbolic strange set characterizes the Hamiltonians that have an invariant torus at the threshold of the break-up. From the critical strange set, one can deduce the critical properties of the tori (self-similarity, universality classes).

List of publications

Books

Chaos, Complexity and Transport (World Scientific, Singapore, 2008)  

• Habilitation.pdf

• lecture notes on Periodic Orbits: How to get them

• Useful routines: nrutil.c and nrutil.h modified from Numerical Recipes (include a definition for tensors in double precision, and 4tensor)

Communications in Nonlinear Science and Numerical Simulation
Chaos, Complexity and Transport: Theory and Applications – June 4-8, 2007 – Le Pharo, Marseille, France.

Chaos Book

HSCoPP'04 - October 21-23, 2004 - Fréjus

ILLUMINYATING ATOMS AND MOLECULES  -- MAY 19, 2006
Symposium IlLUMINYating 2008 - October 1st, 2008 - Centre de Physique Théorique de Marseille