From Nordic Walking in Wess-Zumino-Witten Theory to Deconfined Pseudocriticality

An exciting class of non-Landau transitions are deconfined quantum critical points (DQCP) which exhibit emergent fractional excitations and gauge fields at criticality. The primary example in the study of DQCPs has been a system of half-integer spins on a square lattice with competing interactions. Whether or not this system shows true criticality is a major open question in the field. In fact, numerical simulations for this model provide evidence for weak-first order behavior. The effective field theory describing the behaviour between those orders is a 3D Wess-Zumino-Witten theory with target manifold S⁴. I will discuss a first study of this model using the non-perturbative functional renormalization group. We show that the Wess-Zumino-Witten term gives rise to two possible mechanisms explaining pseudocriticality and drifting exponents: (1) the well-known Walking mechanism and (2) a new mechanism, dubbed Nordic Walking. We provide an estimate for effective thermodynamic critical exponents and their drifts as a function of system size.