Research Activities

Dynamics of DNA conformational changes

The dynamics of DNA conformations induced by mechanical or biochemical constraints is a central issue for biologists and remains challenging for physicists. Indeed, from the biological point of view, it directly concerns the understanding of replication and transcription in vivo, which are out-of-equilibrium processes. On the theoretical side, DNA dynamcis is usually modeled using the classical Rouse dynamcis (or Zimm one, if hydrodynamic interactions are taken into account), where DNA is seen as a simple polymer without internal structure. Although this approach is valid on length scales larger than 100 base-pairs, ... Read more

Energy landscape of Proteins and DNA

Conformational changes in biological systems, such as Proteins and DNA, are made possible by their intrinsic flexibility, and are of paramount importance in understanding biomolecular interactions. The idea is that a global overview of the protein's energy surface is useful for a quantitative understanding of the relationships between structure, dynamcis, stability, and functional behaviour of proteins. Thanks to the continuous increase of the computing power and of the reliability of empirical force fiels, all-atom molecular dynamics simulations become a widely employed computational technique to simulate the dynamics of complex ... Read more

Structure formation in Cosmology

The formation of structures in the Universe is one of the major questions in Cosmology. The growth of sructure in the linear regime of low amplitude fluctuations is well understood analytically, but N-body simulations remain the main tool to probe the "non-linear" regime where fluctuations are large. Approaching this question from the more general perspective of statistical physics and of out-of-equilibrium dynamics of systems with long-range interaction highlights a different look on this problem. In this context, it is natural to develop simplified models to improve our understanding of these systems, ... Read more

Long-range interacting systems

Systems with long-range interactions are characterized by a pair potential which decays at large distances as a power law, with an exponent smaller than the space dimension. Examples are gravitational and Coulomb interactions. The thermodynamic and dynamical properties of such systems were poorly understood until a few years ago. Substantial progress has been made only recently, when it was realized that the lack of additivity induced by long-range interactions does not hinder the development of a fully consistent thermodynamic formalism. This has, however, important consequences ... Read more

last update: January 2017