Probing quantum dynamics with ultracold lithium in optical lattices

We describe recent experiments using Bose-Einstein condensates of lithium in optical lattices to realize a novel quantum sensing platform and probe exotic quantum dynamics. In one experiment we realize a continuously trapped Mach–Zehnder–style atom interferometer in an amplitude-modulated optical lattice. The resulting hybridized Floquet–Bloch band structures define the interferometer arms, complete with Landau–Zener beamsplitters and Bragg mirrors. For specific magic band structures, the interferometric phase is insensitive to lattice intensity noise, enabling compact and programmable force sensing. In a separate experiment, we realize a Fabry-Pérot cavity in the ultrastrong driving regime. This is accomplished by exchanging the roles of light and matter: we confine a matter wave endowed with a relativistic dispersion relation between two repulsive optical potentials which serve as cavity mirrors. Modulating the position of one mirror, we observe the coalescence of an initially diffuse density distribution to a single, localized trajectory, in agreement with theoretical predictions for strongly-driven optical cavities.