1993/10/14 by K. Ziegler, Ziegler, K.
Physics and Astronomy · #Condensed Matter (cond-mat) #FOS: Physical sciences #cond-mat
paper · pdf · doi:10.48550/arxiv.cond-mat/9310031
18 pages, Plain-TeX, TKM 08/93
arxiv created 1993/10/14 · arxiv updated 2009/11/30
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 t depending on the coupling constant U as t<U/4d. This implies an upper bound for the decay length of the Green's function.