"Quantum Control of Hubbard Excitons"
Coherently tuning quantum states with light is a key frontier in the control of quantum materials. Floquet engineering, the coherent dressing of quantum states with periodic non-resonant optical fields, has become an important strategy for quantum control. However, most applications to solid-state systems have targeted weakly interacting or single-ion states, leaving the manipulation of many-body wavefunctions largely unexplored. Here, we demonstrate ultrafast quantum control of a prototypical many-body quantum state, a Hubbard exciton, in the quasi-one-dimensional Mott insulator Sr2CuO3 . We drive the Hubbard exciton with intense midinfrared pulses and interrogate its state with resonant third- harmonic generation. We observe a dynamic renormalization of the third harmonic signal due to a coherent Floquet rotation of the many-body wavefunction between two states with opposite parity. The periodic drive rotates the Hubbard exciton wavefunction by arbitrary angles up to π/2 on the Bloch sphere. By demonstrating on-demand rotations of a many-body quantum state, our work establishes a pathway for quantum control of quantum materials through tailored pulse sequences and the functionalization of Hubbard excitons for quantum sensing applications.
