Piotr Szymczak
Institute of Theoretical Physics
Faculty of Physics, Warsaw University
Hoza 69, 00-681 Warsaw, Poland
telephone: (+48 22) 55 32 256
fax: (+48 22) 621 94 75
email: piotrek[at]fuw.edu.pl
Research
My research focuses on complex systems involving many degrees of freedom in which collective interactions give rise to a rich zoology of physical phenomena. Besides the theoretical analysis, an important tool in tackling these problems are numerical simulations.
Current research topics include:
- dynamics of colloidal suspensions
- dissolution processes in porous media and rock fractures
- the dynamics of a single protein molecule in flow
Even though almost a hundred years have passed since the pioneeering works of Einstein and Smoluchowski, the theory of suspensions of interacting Brownian particles is still a challenge. The analysis of Brownian suspensions is hindered by complicated nature of interparticle interactions which include direct forces such as Coulomb or van der Waals as well as indirect interactions mediated by the solvent. These so-called hydrodynamic interactions are truly complex: they are long ranged, nonlinear in nature, and cannot be expressed as a sum of two-body terms. Their presence makes the problem both interesting and difficult.
During the dissolution of rock fractures the positive feedback between fluid transport and chemical reactions at the mineral surfaces leads to the spontaneous formation of pronounced wormhole-like channels. As the dissolution proceeds, the channels interact, competing for the available flow, and eventually the growth of the shorter ones ceases. Thus the number of channels decreases with time while the characteristic distance between them increases, which leads to the scale-invariant power-law distribution of channel lengths.
Various models of the interaction of dissolving channels are constructed and their properties studied. The results are compared with laboratory experiments and pore-scale simulations of fracture dissolution using a microscopic, three-dimensional numerical model.
See also ICTAM abstract [pdf]
Single protein molecules in a flow field show a surprisingly rich dynamical behavior, as a result of an interplay between the hydrodynamic forces and direct molecular forces. Unfolding of proteins induced by a flow usually involves a larger number of intermediate states than the force-induced unfolding (as in the AFM force clamp). Those features offer potentially wider diagnostic tools to investigate structure of proteins compared to experiments based on the atomic force microscopy.
Teaching: StatMech (in Polish)