The subject of this paper are operators represented on Fock spaces whose behavior on one level depends only on two of its neighbors. Our initial objective was to generalize (via a common framework) the results of arXiv:math/0702158, arXiv:0709.4334, arXiv:0812.0895, and arXiv:1003.2998, whose constructions exhibited this behavior. We extend a number of results from these papers to our more general setting. These include the quadratic relation satisfied by the free cumulant generating function (actually by a variant of it), the resolvent form of the generating function for the Wick polynomials, and classification results for the case when the vacuum state on the operator algebra is tracial. We are able to handle the generating functions in infinitely many variables by considering their matrix-valu
Download