Universal quantum-critical dynamics of two-dimensional antiferromagnets

The universal dynamic and static properties of two-dimensional antiferromagnets in the vicinity of a zero-temperature phase transition from long-range magnetic order to a quantum-disordered phase are studied. Random antiferromagnets with both N\'eel and spin-glass long-range magnetic order are considered. Explicit quantum-critical dynamic scaling functions are computed in a 1/N expansion to two-loop level for certain nonrandom, frustrated square-lattice antiferromagnets. Implications for neutron scattering experiments on the doped cuprates are noted.