Attosecond Chronoscopy of Many-Body Correlations between Bloch Electrons

Correlations between delocalized Bloch electrons are the driving force behind key properties of solids as well as intriguing phase transitions [1]; to directly follow how many-body interactions affect intrinsic electron motion, sub-femtosecond
$(1\ \text{fs}=10^{-15}\mathrm{s})$
temporal resolution is desirable [2]. Multi-terahertz (THz) photon energies are perfectly matched to resonantly probe millielectronvolt (meV) correlation-induced excitations [3]. Yet, resolving the influence of correlations on the trajectories of delocalized Bloch electrons has remained an open challenge.