“…Analytic and numeric studies on such Hamiltonians are quite numerous. 17,18,31,32,33,34,35,36,37,38,39,40,41,42 It is useful to review the strong coupling (t = 0) phase diagram, since when the hopping is nonzero the topology of the phase diagram is rather similar qualitatively and even quantitatively. In the absence of an interaction with the lattice, the SDW phase, which consists of a collection of singly occupied sites, has energy E t=0 SDW = N V , while the CDW phase has alternating empty and doubly occupied sites, and energy E t=0 CDW = N U/2.…”