Ultrafast dynamics of correlated electrons in solids
Experimental activities at advanced photon sources, such as pulsed lasers, high harmonic generation facilities, and X-ray free electron lasers, generate results that challenge our understanding of light-matter interaction and ultrafast dynamics at the femtosecond and sub-femtosecond timescales. These results are particularly difficult to interpret for materials with correlated electrons, where a driving pulse can produce strong non-linear effects. 

In FASTCORR, we answer this challenge with the development of a theory for driven quantum many-body systems that goes well beyond existing methods. This will be accomplished by developing dynamical mean-field theory and its generalizations, e.g., the dual fermion and dual boson theory, to cover out-of-equilibrium phenomena.

We aim to create a solid theoretical foundation on which we will build practical tools that allow to interpret and predict ultrafast time-resolved phenomena of correlated electron systems. This involves (i) the development of fundamental mathematical and physical concepts, (ii) software implementation, and (iii) numerical simulations that will be compared to experiments. Synergies between the three applicants are crucial to achieving the goals of this project.

FASTCORR will result in novel high-performance software that we will distribute freely. These computational tools will enable designed and targeted calculations for driven materials where the electronic structure is determined by strong correlation effects. The developed theory will be used hand in hand with world-leading experimental works in the field of pump-probe measurements and spectroscopy, e.g., as investigated at X-ray free-electron laser laboratories.