For a quantum-mechanical system and a given density, the Zhao-Morrison-Parr method allows to infer the effective potential that yields precisely this density. I will discuss how this can be understood as a limit procedure from Moreau-Yosida-regularized density functionals to the unregularized case. This sheds new insight on the relevance of regularization in density-functional theory and allows to systematically improve density-potential inversion. [mehr]

The interaction of intense light fields with matter is pivotal in various physical contexts, ranging from coherent control schemes in atomic physics to steering the flow of energy in solid-state systems. In particular, joining free-electron beams with ultrafast lasers facilitates the probing of nanoscale dynamics in ultrafast transmission electron microscopy (UTEM) and opens the field of free-electron quantum optics. In my talk, I will briefly introduce the UTEM methodology that combines state-of-the-art TEM with optical pump-probe spectroscopy [1,2], show selected applications in the study of ultrafast dynamics, and discuss the coherent coupling of electrons and photons down to the single particle level. [mehr]