Transport in the mass-imbalanced 1D Fermi-Hubbard model

We study transport in the mass-imbalanced 1D Fermi-Hubbard model using infinite tensor network techniques. We develop a simple model for the frequency dependence of the optical conductivity, valid for strong interactions and large mass imbalances, based on locally-constrained fluctuations. Additionally, we propose a procedure to study these current-current correlators in cold atom experiments.