Form-factors in the Baxter-Bazhanov-Stroganov model II: Ising model on the finite lattice

Abstract

We continue our investigation of the Baxter-Bazhanov-Stroganov or τ^{(2)}-model using the method of separation of variables [nlin/0603028,arXiv:0708.4342]. In this paper we derive for the first time the factorized formula for form-factors of the Ising model on a finite lattice conjectured previously by A.Bugrij and O.Lisovyy in [arXiv:0708.3625,arXiv:0708.3643]. We also find the matrix elements of the spin operator for the finite quantum Ising chain in a transverse field.

25 pages; sections 8 and A.2 are extended, 2 related references are added