ar X iv : c on d - m at / 9 41 20 22 v 2 9 D ec 1 99 4 A Soluble Free - Fermion Model in d Dimensions
نویسندگان
چکیده
We consider a vertex model in d dimensions characterized by lines which run in a preferred direction. We show that this vertex model is soluble if the weights of vertices with intersecting lines are given by a free-fermion condition, and that a fugacity −1 is associated to each loop of lines. The solution is obtained by mapping the model into a dimer problem and by evaluating a Pfaffian. We also determine the critical point and the singular behavior of the free energy.
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