Physical review. B, Condensed matter
Hole-hole effective interaction in the two-dimensional Hubbard model
G. Fano, F. Ortolani, Alberto Parola
Abstract
We present the first exact results of the ground-state energy in the two-dimensional Hubbard model on a 4\ifmmode\times\else\texttimes\fi{}4 cluster for several values of U and fillings. The behavior of the binding energy of two holes as a function of U is discussed together with some analytical results in limiting cases. The analysis of the hole-hole correlation function allows one to determine the range of values of U where binding might be seen.