Recent elastic and inelastic neutron scattering studies of the highly
frustrated pyrochlore antiferromagnet Tb2Ti2O7 have shown some very intriguing
features that cannot be modeled by the local classical Ising model,
naively expected to describe this system at low temperatures. Using the random
phase approximation to take into account fluctuations between the ground state
doublet and the first excited doublet, we successfully describe the elastic
neutron scattering pattern and dispersion relations in Tb2Ti2O7,
semi-quantitatively consistent with experimental observations.Comment: revtex4, 4 pages, 1 Color+ 2 BW figure