Title: Crisis in the Lorentz gas
Speaker: Dr. C. Dettmann
Speaker Info: Northwestern U.
The driven Lorentz gas is a prototypical small nonequilibrium system, amenable to tests of both statistical mechanics and dynamical systems theory. In particular, there are stong connections between macroscopic parameters (such as the average current) and microscopic parameters (Lyapunov exponents). In addition, this system exhibits irreversibility in a statistical sense even though the equations of motion are time reversible, leading to a multifractal attractor which covers the whole phase space. As the field is increased, the attractor suddenly reduces to fractal support, leading to a loss of reversibility on intermediate scales. This transition can be elucidated using dynamical systems approaches, such as symbolic dynamics.Date: Friday, March 7, 1997