Deconfined pseudocriticality in a model spin-1 quantum antiferromagnet

Berry phase interference arguments that underlie the theory of deconfined quantum criticality (DQC) forS=1/2antiferromagnets have also been invoked to allow for continuous transitions inS = 1 magnets including a Néel to (columnar) valence bond solid (cVBS) transition. We provide a microscopic model realization of this transition on the square lattice consisting of Heisenberg exchange (JH) and biquadratic exchange (JB) that favor a Néel phase, and a designedQ-term (QB) interaction which favors a cVBS through large-scale quantum Monte Carlo (QMC) simulations. ForJH=0, this model is equivalent to the SU(3)JQmodel with a Néel-cVBS transition that has been argued to be DQC through QMC. Upon turning onJHwhich brings down the symmetry to SU(2), we find multiple signatures-a single critical point, high quality collapse of correlation ratios and order parameters, 'U(1)-symmetric' cVBS histograms and lack of double-peak in order parameter histograms for largest sizes studied near the critical point-that are highly suggestive of a continuous transition scenario. However, Binder analysis finds negative dips that grow sub-extensively that we interpret as these transitions rather being pseudocritical. This, along with recent results on spin-12models, suggests that deconfined pseudocriticality is the more generic scenario.