Deconfined quantum criticality (DQC) is a beyond-Landau paradigm quantum phase transition predicted to occur in a 2d quantum magnet between a Neel phase and a valence bond solid (VBS) phase. Although the two phases are not related in the traditional symmetry-breaking perspective, field theory predicts that at the DQC transition point the order of the phases fractionalizes and creates an emergent gauge field, letting the Neel-VBS transition generically continuous.

By constructing concrete models that could be simulated to a large scale with quantum Monte Carlo methods, we numerically study the Neel-VBS transition and find that there is an emergent higher symmetry at the first-order transition point up to a very large system size. We also find that there are a number of new perturbations to the DQC point that were previously overlooked, and show that they lead to a different phase diagram, possibly resolving the previously observed discrepancy between theoretical conformal bootstrap calculation and numerical studies.

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