Title:
Anomalous diffusive phenomena in planar hyperbolic billiards

Abstract:
The aim of this talk is to describe the statistical properties of  
various planar hyperbolic billiard models, in particular, Bunimovich  
stadia, Lorentz gases with infinite horizon and dispersing billiards  
with cusps. A common feature of these systems is intermittency, which  
slows down the rate of mixing and results in non-standard limit laws  
(superdiffusive scaling). Further interesting phenomena arise when  
studying the convergence of moments. The new results I am going to  
mention are joint with N. Chernov and D. Dolgopyat.