Deconfined quantum criticality

Certain two-dimensional 5 = quantum antiferromagnets can imdergo a direct continuous quantum phase transition between two ordered phases, an antiferromagnetic Neel phase and the so-called valence-bond ordered phase (where translational invariance is broken). This is in contradiction to Landau theory, which predicts phase coexistence, an intermediate phase, or a first-order transition, if any. The continuous transition is the result of topological defects that become spatially deconfined at the critical point and are not contained in an LGW description. Recently, there has been a great interest in the resulting deconfined quantum critical points. ... 

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