Critical behaviour of structure factors at a quantum phase transition.

We review the theoretical behaviour of the total and one-particle structure factors at a quantum phase transition for temperature T = 0. The predictions are compared with exact or numerical results for the transverse Ising model, the alternating Heisenberg chain, and the bilayer Heisenberg model. At the critical wavevector, the results are generally in accord with theoretical expectations. Away from the critical wavevector, however, different models display quite different behaviours for the one-particle residues and structure factors.