arXiv:cond-mat/0304475 · Journal of Physics A Mathematical and General
Next-nearest-neighbour correlation functions of the spin-1/2XXZchain at the critical region
Go Kato, Masahiro Shiroishi, Minoru Takahashi, Kazumitsu Sakai
Abstract
The correlation functions of the spin-1/2 XXZ spin chain in the ground state are expressed in the form of the multiple integrals. For -1< Delta <1, they were obtained by Jimbo and Miwa in 1996. Especially the next nearest-neighbour correlation functions are given as certain three-dimensional integrals. We shall show these integrals can be reduced to one-dimensional ones and thereby evaluate the values of the next nearest-neighbor correlation functions. We have also found that the remaining one-dimensinal integrals can be evaluated analytically, when nu = arccos(Delta)/pi is a rational number.