Superdiffusive Transport in Chaotic Quantum Systems with Nodal Interactions

We introduce a class of interacting fermionic quantum models in d dimensions with nodal interactions that exhibit superdiffusive transport. We establish nonperturbatively that the nodal structure of the interactions gives rise to long-lived quasiparticle excitations that result in a diverging diffusion constant, even though the system is fully chaotic. Using a Boltzmann equation approach, we find that the charge mode acquires an anomalous dispersion relation at long wavelength ω(q)∼qz with dynamical exponent z=min(2n+d)/2n,2, where n is the order of the nodal point in momentum space. We verify our predictions in one-dimensional systems using tensor-network techniques.