Probing quantum phases and the Hall response in bosonic flux ladders

The focus of this talk is on bosonic flux ladders. First, we touch on a model which is envisioned to be realized in a future quantum gas experiment exploiting the internal states of potassium atoms as a synthetic dimension. Considering specifics of the future experiment, we map out the ground-state phase diagram and report on Meissner and biased-ladder phases. We show that quantum quenches of suitably chosen initial states can be used to probe the equilibrium properties of the dominant ground-state phases.

Second, we concentrate on the Hall response. While flux ladders are the most simple lattice models giving rise to the Hall effect, the theoretical description of the ground-state Hall response in these systems remains a tricky problem and an active line of research. We discuss feasible schemes to extend measurements of the Hall polarization to a study of the Hall voltage, allowing for direct comparison with solid state systems. Most importantly, we report on characteristic zero crossings and a remarkable robustness of the Hall voltage with respect to interaction strengths, particle fillings, and ladder geometries, which is unobservable in the Hall polarization.