Statistical Physics far from Equilibrium

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

TECHNICAL SUMMARY This award supports theoretical research and education in a continuing effort to understand the complex behavior in interacting many-particle systems driven far from thermal equilibrium. Unlike their equilibrium counterparts, these systems "both physical and biological" cannot be described by the well established framework of Boltzmann and Gibbs. One essential difference is that these systems are in contact with more than one reservoir in such a way that nontrivial fluxes through the systems persist, even when they are in time-independent states. Good examples include all living organisms, the earth as an ecosystem, and many aspects of our modern infrastructure. The key challenge is to devise a reliable theoretical framework which predicts macroscopic observables from the underlying microscopic dynamics. An overarching framework for non-equilibrium statistical mechanics is lacking. The PIs will study the least complex models which include essential characteristics of far-from-equilibrium physics. The PIs will focus on models with the potential for applications to biological systems. The totally asymmetric simple exclusion process will be a focus of study. Many properties of the original model are known analytically. However, generalizations of the model become the building blocks for a quantitative approach to modeling protein production in a cell. Progress in this field will contribute to understanding biological transport processes, inspire possible ways to design and synthesize proteins, as well as to valuable insights for addressing fundamental issues in non-equilibrium statistical physics, such as the role of non-trivial probability current loops in configuration space. Given the range of topics and methods in this research, it lends itself readily to the education of young scientists at virtually all levels. In this way, this award contributes to the training of the next generation of a globally competitive workforce. NONTECHNICAL SUMMARY This award supports theoretical research and education in statistical physics of systems driven far from equilibrium. Living things provide an important example of a system composed of many particles or parts that is far from the balanced state known as equilibrium. The main goal of this research is to elucidate the foundations of a theoretical and conceptual framework for materials and other systems that are far from equilibrium. The PIs seek an overarching principle which generalizes the extremely successful fundamental hypothesis of the field of equilibrium statistical mechanics. This research covers a wide range of topics and exploits a variety of methods: from the simplest mathematical models to models of complex living systems and from readily accessible computer simulations to sophisticated field theoretic techniques. A central focus of this research lies at the interface of biology and materials research. The PIs will study protein production by messenger RNA in cells. It will be modeled as an assembly-line-like activity and studied with both simulations and powerful tools in mathematics and statistics. This research will apply the insights gained to investigate a wider range of transport systems, from traffic flow to information on the Internet. Given the range of topics and methods in this research, it lends itself readily to the education of young scientists at virtually all levels. In this way, this award contributes to the training of the next generation of a globally competitive workforce.