Our activities are focused on fundamental questions in modern theoretical physics. Typically, we construct and study simple models that allow us to grasp the main features of physical systems, that exist in real life or in the lab.
Our research efforts currently cover the following topics.

Publications récentes:

Aging in the Long-Range Ising Model
Henrik Christiansen, Suman Majumder, Malte Henkel, and Wolfhard Janke
Physical Review Letters (2020) 125, 180601

Generalized Hydrodynamics on an Atom Chip
M. Schemmer, I. Bouchoule, B. Doyon, and J. Dubail
Physical Review Letters (2019) 122, 090601

Flexoelectric fluid membrane vesicles in spherical confinement
Niloufar Abtahi, Lila Bouzar, Nadia Saidi-Amroun and Martin Michael Müller
Europhysics Letters (2020) 131, 18001 

Classical Kalb-Ramond field theory in curved spacetimes
Bertrand Berche, Sébastien Fumeron, and Fernando Moraes
Physical Review D (2021) 05, 105026

Helical Superstructure of Intermediate Filaments
Lila Bouzar, Martin Michael Müller, René Messina, Bernd Nöding, Sarah Köster, Hervé Mohrbach, and Igor M. Kulić
Physical Review Letters (2019) 122, 098101

Thèmes scientifiques :

Physics of aging

How do materials age? How to model aging phenomena? One powerful approach that we are developing is to look for scale invariance, both in space and in time, of concrete microscopic models, that we study analytically and numerically. Those include reaction-diffusion models, or growth models, in particular those that fall in the Kardar-Parisi-Zhang universality class (both in one dimension and higher dimensions).

Disorder and phase transitions in statistical physics

Disorder – like impurities in a material, defects in the arrangement of the atoms, etc. – in a physical system undergoing a classical or quantum phase transition may have drastic consequences. First-order phase transitions are smoothed and may even become continuous. The universal behaviour of thermodynamic averages near the transition point may also change in the presence of disorder. We study these phenomena with large-scale numerical simulations in lattice spin models.

Dynamics of open and closed quantum systems

Many-body and few-body quantum systems are now routinely created and manipulated in cold atoms experiments. How to model such experiments ? What is the best way to simulate the collective behavior of many atoms that are all interacting ? How to understand quantum decoherence ? We study such questions by relying on state-of-the-art analytical and numerical techniques, such as numerical implementations of the Bethe Ansatz and form factor calculations, large-scale approaches like hydrodynamics
and/or field theory, as well as exact solutions of simple models.

Soft Matter

Physical systems sensitive to small perturbations (thermal fluctuations, small external fields or mechanical stresses etc.) correspond to so-called soft matter. (Dipolar) Colloidal suspensions and granular matter are under heavy investigation where the fundamental link between pair interaction and macroscopic structure/response is sought. These materials have high potential applications and constitute a formidable theoretical challenge due to the intrinsic long range (and possibly anisotropic) interaction there. On the other hand, elastic and fluid membranes in and out-of-equilibrium are also subject of active Research. Focus is brought to membrane-like objects whose configuration is governed by an interplay of elasticity and geometry . Problems on different scales are discussed such as the macroscopic growth of thin tissues as well as the symmetry-breaking of fluid membranes due to confinement or constriction.

Analogue gravity

The recent breakthroughs of gravitational interferometers have provided cosmology with a new tool to investigate the universe and the exotic objects that it may contains (binary black holes, neutron stars…). However, informations provided by either classical “optical” astronomy or gravitational astronomy can be supplemented by what is called “analogue gravity systems”. These latter consist mostly in condensed matter systems that share common properties (spacetime geometry, dynamics, scaling laws…) with their cosmological counterparts. Among the most well-known of these analog systems, there are hypersonic fluid flows (used as artificial black holes to investigate Hawking radiation), disclinations in liquid crystals (used as cosmic strings networks) or more recently metamaterials (used to mimic any spacetime geometry, as prescribed by transformational optics).

Mathematical physics

Recently new classes of exactly solvable quantum potentials associated to the recently discovered exceptional orthogonal polynomials (X-OP) have been the subject of active researches. They appear to open new perspectives on some integrable nonlinear ODE and PDE. We study in particular the connection between X-OP and hierarchies of rational and special functions solutions of the Painlevé equations and higher order Painlevé chains.

Collaborations principales :


Institut d’Astrophysique de Paris (Sorbonne Université)
LEM3, Université de Lorraine
Institut d’Optique, Université Paris-Saclay, Palaiseau
Centre Européen de Sciences Quantiques, Université de Strasbourg
Laboratoire de Physique Théorique et Modèles Statistiques, Université Paris-Saclay

Center for Fluids and Complex Systems, Coventry U, UK
Institute for Condensed Matter Physics, Academy of Sciences, Lviv Ukraine
Universidad San Francisco de Quito, Quito, Ecuador
ESPOL, Guayaquil, Ecuador
Universidad Pernambuco, Recife, Brazil
University of Leeds, UK
Università del Salento, Italy
Universidade Federal Rural de Pernambuco, Brasil
Seoul National University, South Korea
University of Rochester, USA.
Forschungszentrum Jülich, Germany
SISSA, Trieste, Italy
Universidade de Lisboa, Portugal
Universite de Sarrebruck, Germany
Virginia Tech, USA
King’s College London, London, UK
Penn State University, USA