Raman momentum lattice with ultracold atoms

We developed internal and external states combined momentum lattice by implementing both Bragg and Raman couplings with ultracold atoms. Such Raman momentum lattice provides additional engineering knobs. By introducing loss in one internal state, we realize a dissipative Aharonov-Bohm chain—non-Hermitian topological model with NHSE. We identify signatures of the NHSE in the condensate dynamics and perform Bragg spectroscopy to resolve topological edge states against a background of localized bulk states. With two internal states, we also realize the AB cage model, and the flat band localization is observed. By introducing disorders to the AB cage system, a transition from flat band localization to Anderson localized is observed. Our Raman momentum lattice has good potential for further quantum-simulating novel physics.