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Stability of Insulating Phases in the Hubbard Model: a Cluster Expansion

K. Ziegler
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Abstract

The stability of the insulating regime of the Hubbard model on a $d$-dimensional lattice, which is characterized by an exponential decay of the Green's functions, is investigated in terms of a cluster expansion. This expansion for the Green's function is organized in terms of connected clustered transfer matrices. An upper bound for the expansion terms is derived for the hopping rate ${\bar t}$ depending on the coupling constant $U$ as ${\bar t}<U/4d$. This implies an upper bound for the decay length of the Green's function.

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K. Ziegler. 1993-10-14. Stability of Insulating Phases in the Hubbard Model: a Cluster Expansion. https://arxiv.org/abs/cond-mat/9310031

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