Radiation from Matrix Models
I give an overview of work characterizing radiation in generic four-dimensional conformal field theories. I argue that for theories with conformal scalars, the radiated energy is not positive definite and the radiated power is not Lorentz invariant. I then determine the coupling dependence of radiation, for N=2 superconformal field theories in the planar limit. This involves a purely combinatorial solution of certain matrix models, in terms of tree graphs.