Date of Original Version
We calculate the zero-temperature q-dependent susceptibilities of the one-dimensional, S=1/2, transverse Ising model at the critical magnetic field and of the isotropic XY model in zero field which have not been previously determined. Our method, which is based on a rigorous method of calculating dynamic correlation functions for these models, provides precise numerical values for the susceptibilities at wave numbers q=kπ/M for integral M and odd integral k, as well as exact analytic results for the dominant singularities at q=0 and q=π.
G. Müller and R.E. Shrock. Wave-number dependent susceptibilities of one-dimensional quantum spin models. Phys. Rev. B 31 (1985), 637-640.
Available at http://dx.doi.org/10.1103/PhysRevB.31.637.