Cette page web en français

After a Ph.D. on the electronic properties and the stability of quasicrystals (1990; ENS Paris & Univ. P. & M. Curie), I spent two years at the AT&T Bell Labs (NJ, USA). There, I worked on high-Tc superconductivity but also started working on non-equilibrium statistical physics, which has since become my main domain of research: stochastic processes and their physical applications, phase separation and coarsening systems, physics of society, and behavioral biology…

In particular, since 2014, I have been fully devoted to the study of collective phenomena (motion, decision-making…) in animal and human groups, developing a fruitful collaboration with Guy Theraulaz and his group at CRCA/CBI in Toulouse.

I design experiments with Guy Theraulaz, conduct them on humans (but not on fish), process and analyze the data, and develop behavioral models inspired by tools from statistical physics (see the Research topics tab).

In addition to my pure research activities, I dedicate a significant amount of time to teaching as well as to science communication and outreach (see the Popularization tab).

Some press releases on my recent research

• Deception and collaboration in human groups interacting through stigmergy (CNRS press release)
• Collective movements and separation task in human groups (Article in the CNRS Journal)
• Collective estimation tasks in human groups under influence (CNRS press release)
• How stress can boost the sensitivity and adaptability of fish schools (CNRS press release in French; LPT news in English)
• Hydrodynamic interactions in fish schools (CNRS press release; Editor’s choice in Physical Review Letters; article in Physics Magazine)
• Domino effect in collective decisions of fish schools (CNRS press release on CRCA’s website)

Physics of society and behavioral biology

• Collective phenomena in fish schools
  • Measuring social interactions in fish schools and animal groups [86,89]
  • Modelization of fish schools and comparison with experiments [78,79,80,84,86,87,94,95,102,A8]
  • Collective decisions in fish schools [79,80,84,87]
  • Effects of hydrodynamic interactions in fish schools [85] (CNRS press release; Editor’s choice in Physical Review Letters ; article in Physics magazine)
  • Fish interactions and collective states in varying light conditions [98,103]
  • Fish under stress switching to a critical state [103] (CNRS press release in French; LPT news in English)
  • Bioinspired robotic and drone platforms implementing fish social interactions [87,96,101,A9,A10]
  • Machine learning and kernel methods to produce realistic fish trajectories [100,101]
• Collective phenomena in human groups
  • Measuring social interactions in human groups [88,89]
  • Estimation tasks in human groups [82,90-92] (CNRS press release)
  • Cooperation and deception through stigmergic interactions in human groups [97] CNRS (CNRS press release)
  • Collective motion and separation task in human groups [88] (Article in the CNRS Journal)

• Collective phenomena in other living systems
  • Theory of active particles [78,85,88]
  • Collective motion in cells [83,93]
• Models of competition
  • Theory of poker tournaments [66] (Scientific American News)
  • The leader problem as a model of biological evolution [63,66]
  • Other models of competition (baseball, game theory…) [72,73]

Non-Equilibrium Statistical Physics

• Coarsening dynamics
  • Exact conserved phase separation model [17]
  • Potts model autocorrelation exponent [25,26]
  • Theoretical and experimental study of Langmuir films [22,24]
  • Soap froths [21,25-27]
  • Conserved systems autocorrelation exponent [56]
• Reaction-diffusion and other aggregation models
  • Exactly solvable river model [18]
  • Exact results for Smoluchowski’s equations [33,36,38]
  • Exact results for ballistic aggregation [46]
  • Approximate solution of directed percolation [50]
• Properties of random walks (persistence (Science Magazine News), diffusion, disorder…)
  • General theories for the persistence exponent of a Gaussian non-Markovian walker [30-32,34,35,40,64,71]
  • A novel critical exponent for spin systems [32]
  • Persistence and global persistence in spin systems at zero and finite temperature [30,37,39]
  • Nontrivial persistence in the simple diffusion equation [31,64,71]
  • Probability distribution of the maximum of a smooth temporal signal [64,71]
  • Exact models with disorder and absorption [41,47,62,74]
  • Dynamical phase transitions, directed percolation [18,50,84]
  • Penetration or screening length of a random walker in a random medium of absorbers [62]
  • Screening length in diffusion limited aggregation (DLA) [62]
• Decaying turbulence
  • Exact results for velocity/acceleration distributions and correlation functions [42,45]
  • Renormalization group, kinetic theory, simulations, and comparison with experiments [29,43,77]
  • Simulations [43,44]
• Self-gravitating systems
  • Statics of self-gravitating Brownian/Lévy particles (canonical and microcanonical ensembles) [47-49,51, 65,67-70,76,99,A6]
  • Collapse dynamics of self-gravitating Brownian/Lévy particles in all dimensions [47-49,51-55,57-61, 65,67-70,76,A6]
  • Post-collapse dynamics of self-gravitating Brownian particles in D>2 [52,55,61,A6]
  • Analogy with the dynamics of the Bose-Einstein condensation [61]
  • Analogy with chemotactic aggregation of bacteria [54,57,67,70,76,A6]

Quasicrystals

• Transport theory of real quasicrystals
  • 2D and 3D simulations [A5,16]
  • Phenomenology [A2,A3,A5]
• Electronic and localization properties (1D-3D)
  • RG in D>1 [1,3,5]
  • Simulations [9,11,16]
  • Perturbative methods and exact results in D=1 [2,4,7,8,14,28]
• Stability
  • General exact results for electronic stability in D=1 [8,10]
  • Random tiling model [15]

Correlated Fermions

• Marginal and non-Fermi liquids [19,20,23]
• Theory of the non-Fermi-liquid transition point in the two-impurity Kondo model [19]
• Ground-state fidelity susceptibility near a quantum critical point [75]

Quantum Chaos

• Berry’s phase in an atomic system [6]
• Quantum chaos in quasicrystals
  • Level statistics, diffusion, and energy spectrum [11,16]
  • Quantum kicked rotator and diffusion in a quasicrystal [12]
• Introduction of level statistics in correlated electron systems [13]

Numbers between brackets refer to the corresponding articles in my publication list

Scientific talks

• When poor little fish meet AI, VR, robots, and drones! English ; Français
• Persistence of a random temporal signal : applications & approximate methods English
• Collective information processing in human phase separation English ; French
• Analytical and numerical study of a realistic model for fish schools : English
• Synchronization in long-range interacting systems : English
• Statistical physics of competition : poker tournaments, the “leader problem”, baseball/football championships, and tree games : English
• Decaying two-dimensional turbulence : effective merging dynamics of two and three fluid vortices : English
• Introduction to anomalous diffusion and persistence of random walkers : English
• Introduction to reaction/diffusion/aggregation processes : English
• Universal properties of poker tournaments : persistence, the “leader problem”, extreme value statistics : English
• Self-gravitating Brownian particles : English
• Time correlations in out of equilibrium spin systems : English

Popularization talks in English

• Popularization talk on unconventional domains of research in physics “Physics out the beaten track”(pdf) : French / English

• List of publications and conferences (PDF)
• Preprints on arXiv/bioRxiv/PubMed/PsyArXiv
• My ORCID and ResearchGate pages
• Citations on Google Scholar (free access) and Web of Science (account needed for full access)

My publications on HAL

• Born 26^th March 1967 in Boulogne-Billancourt, France
• Graduate from the École Normale Supérieure in Paris (1986-1990)
• Agrégé de Mathématiques in 1990 (rank: 9^th)
• Ph.D. in Theoretical Physics, Electronic properties and stability of quasicrystals, Université P. & M. Curie and ENS (Paris, Nov. 1990); Ph. D. Advisor: R. Mosseri
• Chargé de recherche CR2 at CNRS (section 02) in Oct. 1990
• Post-doctoral Associate at AT&T Bell Labs, USA (1992-1994); Advisor: C. M. Varma
• Chargé de recherche CR1 at Laboratoire de Physique Théorique (Toulouse) in 1994
• Bronze Medal of CNRS in 1994
• Directeur de recherche DR2 since Oct. 2005
• Head of the Laboratoire de Physique Théorique from Jan. 2007 to Dec. 2015
• Outstanding Referee of the American Physical Society since 2012
• Directeur de recherche DR1 since Feb. 2021