Universal KPZ dynamics in integrable quantum systems

A broad class of integrable spin chains with a non-Abelian symmetry have recently been proven to exhibit anomalous, superdiffusive transport with a dynamical exponent of 3/2. In the specific context of the integrable, SU(2)-symmetric Heisenberg spin-half chain, both numerics and experiments, have recently shown that these superdiffusive dynamics fall into the Kardar–Parisi–Zhang (KPZ) universality class. Leveraging a novel numerical technique, termed density matrix truncation, we combine and generalize these previous results to show that KPZ transport occurs not only in non-Abelian symmetric integrable models, but also in their periodically-driven and supersymmetric counterparts. Moreover, by analyzing symmetry-breaking perturbations, we observe direct evidence for the purported microscopic mechanism underlying this anomalous transport behavior.