The behavior of two holes in the t-J model is analyzed on the infinite square lattice by an extension of the self-consistent Born approximation, which has proved to be very accurate in the single-hole problem. The main ingredient of our theory is the exact form of the eigenstates. Our results agree well with those of previous numerical studies of the problem. The d-wave bound state is found to have the lowest energy with a critical value J/t|c approximately=0.4, and there is no indication for a crossover between the d-wave and the p-wave bound states.
 

Europhysics Letters, 47 227-32, 1999.