We calculate the spectral densities for two impurities inside an elliptical
quantum corral using exact diagonalization in the relevant Hilbert subspace and
embedding into the rest of the system. For one impurity, the space and energy
dependence of the change in differential conductance Δ=dI/dV observed
in the quantum mirage experiment is reproduced. In presence of another
impurity, Δ=dI/dV is very sensitive to the hybridization between
impurity and bulk. The impurities are correlated ferromagnetically between
them. A hopping ≳0.15 eV between impurities destroy the Kondo
resonance.Comment: 4 pages, 4 figure