Some Hamiltonian models of friction

Mathematical results on a model describing the motion of a tracer particle through a non-interacting Bose-Einstein condensate are described. In the limit of a very dense gas and for a very large particle mass, the dynamics of the coupled system is determined by classical nonlinear Hamiltonian equations of motion. The particle's motion exhibits deceleration corresponding to friction with memory caused by the emission of Cerenkov radiation of gapless modes into the gas. A more general class of models involving interacting Bose gases will be studied in forthcoming papers. (C) 2011 American Institute of Physics. [doi:10.1063/1.3619799]