Physics of Biological Systems
The central goal of our work is to contribute to a quantitative, functional understanding of biological systems, using concepts and methods of statistical physics. Our genome is not just a collection of genes but a strongly correlated system shaped by multiple interactions between genes. Molecular information processing takes place through a number of networks governing the regulatory interactions between genes, the interaction between proteins, metabolic pathways in the cell etc. Hence, as it has become clear in recent years, biological function cannot be understood at the level of single genes but requires the study of their interactions at the level of the entire genome. To understand various aspects of this "many-particle" system, we are engaged in a broadly based research program involving the statistics of sequences and molecules, the structure and dynamics of bio-molecular networks, and the statistical dynamics of populations. Building a quantitative theory requires the confluence of ideas from molecular genetics, evolution biology, biophysics, statistical mechanics, and bioinformatics, and all of these play a role in our work. Future conceptual challenges will arise from large-scale comparisons of different species, which will allow to infer patterns of evolutionary dynamics and, ultimately, make genomics a predictive science.
Recent projects and publications
Physics of Nonequilibrium and Disorder
An important subject of modern statistical physics and a focus of our work are systems away from normal thermodynamic equilibrium, such as growth phenomena and `frozen' disordered materials (which are important, for example, in the theory of superconductivity). These systems are ubiquitous in nature, and they are a challenge for the theorist since traditional methods often fail. My work has been focused on nonperturbative aspects of surface growth [1,2] and turbulence [3]. Nonequilibrium statistical mechanics is also crucial for a quantitative understanding of biological evolution.
Statistical Mechanics and Field Theory
In the past, I have worked on conformal field theory and the theory of the renormalization group [1]. Subsequent work has focused on applications of field theory to `soft' condensed matter systems such as surfaces and polymers. These objects undergo conformation changes that can be understood as (de-)localization phenomena. Rough crystal surfaces, in particular, are important systems for material science where this theory compares favorably with experiments [2]. Recently the field-theoretic framework has been generalized to fluid membranes and semiflexible polymers [3], and to the freezing transition of RNA heteropolymers. Field-theoretic concepts have multiple applications to biological systems for the dynamics of populations both in sequence space and in real space.
