Regine Frank works on condensed matter theory and light-matter interactions. Her research activities comprise quantum-mechanical and quantum-field-theoretical methods. Photonic and electronic transport, coherence and decoherence effects are of particular interest. Recent activities are on non-equilibrium Keldysh-description of correlated electrons, cold fermions, polaritonics and numerical methods such as dynamical mean field theory in the non-equilibrium Floquet-Keldysh description using iterative perturbative solvers (DMFT-IPT).

Further transport of light and matter in disordered scattering potentials is to be mentioned, diagrammatic self-consistent theory, especially Vollhardt-Wölfle theory of photons in localizing as well as non-conserving, non-linear three dimensional granular solids. One possible application is random lasing.