Dynamic structure factor of the transverse Ising model

We report the first analytic study of real time and frequency dependent behaviour at T= infinity of the 2D square lattice transverse Ising model. Our study, along with known results in the 1D case, in the mean field or infinity D case and in other studies, helps understand the experimentally obtained longitudinal dynamic structure factor of the induced moment ferromagnet LiTbF₄ studied by Youngblood et al., and is consistent with the studies of Kotzler et al.