Anomalous spin transport in near-integrable spin chains

This talk explores anomalous high-temperature spin transport in
near-integrable one-dimensional systems, using the XXZ model as a central
example. I will discuss three cases: (i) spin superdiffusion at the
isotropic point and its sensitivity to weak energy-conserving
perturbations, where the fate of superdiffusion depends on perturbation
symmetry; (ii) diffusion in the easy-axis regime, where
integrability-breaking perturbations induce a sharp change in the
diffusion constant, marking a transition to normal diffusion; and (iii)
subdiffusion induced by a finite Stark potential, leading to fractonic
transport in large systems and challenging the notion of Stark many-body
localization. Overall, the talk will provide insights into the robustness,
emergence, and crossover of anomalous transport phenomena in quantum spin
chains.