Correlation functions of the openXXZ chain: I

Abstract

We consider the XXZ spin chain with diagonal boundary conditions in the framework of the algebraic Betheansatz. Using the explicit computation of the scalar products of Bethe states and arevisited version of the bulk quantum inverse problem, we calculate the elementary buildingblocks for the correlation functions. In the limit of a half-infinite chain, they are obtainedas multiple integrals of usual functions, similar to the case of periodic boundaryconditions.