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The Heisenberg model

A study of the Heisenberg model by means of the COM is reported in Ref. [111]. In particular the following properties have been computed:

  1. The response functions (i.e., static spin susceptibility) [111]

    The COM results have been compared with the ones obtained by:

The 2D antiferromagnetic Heisenberg model has been investigated by considering a two-pole approximation in the bosonic sector. The development of a short range antiferromagnetic order has been described by a nearest neighbor spin-pair order parameter. The calculation of the static susceptibility as a function of the temperature shows a crossover from the Curie-Weiss behavior to the spin liquid one. The agreement with numerical and analytical approaches is reasonably good.

avella 2002-06-10