The longitudinal susceptibility of an XY spin-chain

A previously unsolved problem has been solved numerically using transfer ma trix renormalization group analysis, based on a density matrix renormalizat ion group idea. This calculation leads to a high-precision prediction of th e value of susceptibility in the x- or y- directions of an XY spin-chain, b ecause in the calculation the transfer matrix idea is incorporated and a th ermodynamic limit is ensured. From this calculation the susceptibility at z ero temperature is predicted for a spin-1/2 antiferromagnetic XY model in o ne dimension.