New Comparisons for Local Quantities of the Two-Dimensional Hubbard   Model
  We have compared the results of our approximation scheme, the composite operator method, for the double occupancy and the internal energy of the two-dimensional Hubbard model with numerical data obtained by means of the Lanczos and quantum Monte Carlo schemes. The agreement is very good at both half-filling and away from it showing how reliable is the approximation scheme. 
A. Avella and F. Mancini (University of Salerno, Italy)