We study states in the superconducting gap induced by magnetic impurities
using self-consistent quantum Monte Carlo with maximum entropy and formally
exact analytic continuation methods. The magnetic impurity susceptibility has
different characteristics for T_{0} \alt T_{c0} and T_{0} \agt T_{c0}
(T0โ: Kondo temperature, Tc0โ: superconducting transition temperature)
due to the crossover between a doublet and a singlet ground state. We
systematically study the location and the weight of the gap states and the gap
parameter as a function of T0โ/Tc0โ and the concentration of the
impurities.Comment: 4 pages in ReVTeX including 4 encapsulated Postscript figure