Deconfined Quantum Criticality and Conformal Phase Transition

We introduce a new perspective on deconfined quantum criticality within a field-theoretic framework. We show that in the allegedly weak first-order transition regime from a N\'eel to a valence-bond solid in $SU(N)$ antiferromagnets, a so-called conformal phase transition leads to a genuine deconfined quantum critical point. In such a transition, the gap vanishes as the critical point is approached, while the spin stiffness at zero temperature has a universal jump at the critical point. We discuss the logarithmic corrections to scaling observed numerically and interpret them in terms of the conformal phase transition. The behavior of the N\'eel and valence-bond solid susceptibilities are discussed at zero and finite temperatures.