  Magnetic diffraction patterns which exhibit more than one discrete set of
symmetry related peaks have been explained by the simultaneous coexistence of
more than one magnetic polarisation and propagation vector, k, in the
scattering amplitude. In this work we suggest using such multi-k magnetic
structures as prototypical multiple order parameter systems. The examples
studied are uranium rocksalts, which exhibit magnetic diffraction patterns, the
indexing of which requires three orthogonal propagation wavevectors. In the
cubic phase these systems exhibit, in addition to the three sets of symmetry
related magnetic diffraction peaks, a set of additional Bragg peaks which have
been observed by both neutron and x-ray resonant scattering. An interpretation
of the neutron diffraction form factor of these peaks is presented, identifying
these peaks as signatures of quantum coherence between the three orthogonal
order parameters.
