Many-body dynamics and Kondo coherence collapse in an ultrafast driven Kondo insulator

Intense ultrafast pulse-driven electronics have provided systematic insights into the dynamics of electrons in condensed matter systems, which opens up prospects for quantum control of solids and all-optical band structure reconstruction. So far the studies have been carried out in solids where ‘bare’ electronic excitations dominate quantum dynamics. However, the underlying many-body dynamics due to correlations and couplings with other degrees of freedom such as lattice, spin or orbitals, has remained out of reach. Here, we introduce an ultrafast laser to optically pump and probe a Kondo lattice, in which conducting electrons strongly couple with magnetically local moments. The laser field excites collective doublon-hole pairs and drives a transient Kondo insulator melting, which are documented through the time-, frequency-, and momentum-dependent influence on the electronic structure. After photo-excitation, doublon-hole re-collision results in high-frequency photon emission. The information that we demonstrate as being accessible with time- and angle-resolved photo-electron spectroscopy and high-harmonic generation spectra, will stimulates the investigation of non-equilibrium dynamics and non-linear phenomenon in heavy-fermion systems.