Dynamical incommensurability in the 2D Hubbard model

The recent discovery of incommensurate fluctuations in yttrium compounds ha s reopened the problem of finding new appropriate frameworks to describe th e variety of experimental features presented by cuprate superconductors. Ac cording to this, the imaginary part of the dynamical spin magnetic suscepti bility of the Hubbard model has been studied by means of the composite oper ator method. By varying the frequency, the crossover between the two antife rromagnetic regimes has been found. The incommensurability issue has been s tudied and discussed. (C) 1999 Elsevier Science B.V. All rights reserved.