We will examine the current progress in constructing non-quasiparticle transport theories of non-Fermi liquid phases that emerge ubiquitously in strongly correlated quantum materials.
To this end, we will discuss the Kubo formula and also the somewhat less known Mori-Zwanzig memory matrix approach. The latter method permits a nearly hydrodynamic description of the problem, which is especially suited to address strongly-interacting quantum states. As an application, we will discuss our recent studies with regard to the identification of non-Fermi liquid signatures in the transport properties of some relevant models for high-Tc superconductivity.