Observation of high harmonic generation from a Mott insulating cuprate

High harmonic generation (HHG) is an extremely nonlinear optical phenomenon in which coherent photons at integer multiples of the fundamental electromagnetic drive frequency are emitted. While initially discovered and extensively studied in atomic and molecular gases, recent breakthroughs of HHG in condensed matter demonstrated its unique strength ranging from spectroscopic characterization of electronic bands and quantum geometry to resolving femto- to attosecond charge dynamics. Yet, despite these opportunities, we still lack understanding of how many-body interactions shape the HHG responses from a strongly correlated electron system. In this talk, I will present our recent demonstration of HHG in a prototypical cuprate Mott insulator. Implications for the mechanisms of high harmonics and dynamical many-body effects on the harmonic emission process will be discussed. Moreover, a Hubbard model simulation based on exact diagonalization that reproduces experimental observations will also be highlighted.