Non-adiabatic functionals in TDDFT from the Connector Theory

Time-dependent density functional theory (TDDFT) has become a widely used method for the description of electronic spectra and responses, as well as an important tool for real-time electronic dynamics. However, these calculations use predominantly adiabatic functionals, i.e. with no memory (or frequency) dependence, for the exchange correlation potential (or kernel). With this limitation, accurate description of non-adiabatic phenomena such as resonantly-driven dynamics or dynamics far from the ground-state remains usually out of reach. Recently, a new approach called "Connector Theory" (COT), that makes use of the knowledge obtained on model systems to compute quantities in physical systems, has been developed. COT is in principle exact, but in practice approximations are needed to make it tractable. In this talk, we develop new non-adiabatic functionals for the exchange-correlation potential using the COT approach. We present the various approximations and models chosen to derive our functionals and discuss the quality of the resulting time-dependent quantities obtained in model and realistic systems.