A weak coupling theory for La2CuO4: Ln2 parquet approach

Abstract

In the model of two-dimensional electrons with a square Fermi surface , ln2-parquet equations are derived and numerically solved. It is suggested that this model can describe La2CuO4 in the weak coupling limit. The main result is a strong difference between the Hubbard model with one charge and the model with four effective charges, describing an interaction of a general form.