Delocalization in Tight-Binding Hamiltonians: A Modified Coupled-Cluster   Based Investigation
  The nature of delocalization in a 1D system ruled by a tight-binding Hamiltonian is investigated. Using a local evaluation of the ground state energy, it is shown that the range of the delocalization effects is rather limited. The method is applied to 1/2 and 1/4 filled systems. 
Arnaud Boullanger and Vincent Robert