  We study a recently discussed XX spin chain with non-local dephasing
[arXiv:2310.03069] in a steady-state boundary-driven setting, confirming
superdiffusive magnetization transport in the thermodynamic limit. The
emergence of superdiffusion is rather interesting as the Lindblad operators
causing it are a coherent sum of two terms, each of which would separately
cause diffusion. One therefore has a quantum phenomenon where a coherent sum of
two diffusive terms results in superdiffusion. We also study perturbations of
the superdiffusive model, finding that breaking the exact form of dissipators,
as well as adding interactions to the XX chain, results in superdiffusion
changing into diffusion.
