Trapping of a random walk by diffusing traps
  We present a systematic analytical approach to the trapping of a random walk by a finite density rho of diffusing traps in arbitrary dimension d. We confirm the phenomenologically predicted e^{-c_d rho t^{d/2}} time decay of the survival probability, and compute the dimension dependent constant c_d to leading order within an eps=2-d expansion. 
F. van Wijland (Pole Matiere et Systemes Complexes, Paris VII and   Laboratoire de physique theorique, Orsay)