Abstract: A point particle is moving freely inside a time varying domain while experiencing elastic reflections on its boundary. The energy is not conserved and can reach arbitrarily large value (Fermi acceleration). This phenomenon was originally proposed by Fermi and Ulam as the mechanism for the acceleration of high energy cosmic rays. It is a subject of intense current research worldwide. According to many numerical simulations in various billiard systems where Fermi acceleration is observed the mean velocity of an ensemble of particles follows the power law , where is the number of collisions and is the system dependent acceleration exponent. I shall present the first theoretical derivation  of for important class of conformally breathing billiards. I shall also analyze the velocity dynamics of a single trajectory, independent of the properties of the underlying static billiard.
 Batistić B and Robnik M Fermi acceleration in time dependent billiards: Theory of the velocity diffusion in conformally breathing fully chaotic billiards, submitted to J. Phys. A: Math. Theor. 2011
Seminarsko predavanje bo v četrtek 14. aprila 2011 ob 15:15 uri v seminarski sobi CAMTP, Krekova 2, pritličje. Vljudno vabljeni vsi zainteresirani, tudi študenti.