Low-dimensional quantum gases in curved geometries

Atomic gases confined in curved geometries are characterized by distinctive features that are absent in their flat counterparts, such as periodic boundaries, local curvature and nontrivial topologies. The recent experiments with shell-shaped quantum gases and the study of ring-shaped superfluids point out that the manifold of a quantum gas could soon become a controllable feature, thus enabling the fundamental study of curved many-body quantum systems. In this Perspective article, we review the main geometries realized in the experiments, analysing the theoretical and experimental status on their phase transitions and on the superfluid dynamics. As our outlook, we delineate the study of vortices, the few-body physics and the search for analogue models in various curved geometries as the most promising research areas.Atomic gases, usually confined in flat geometries, are now experimentally realized also in curved settings. This Perspective article analyses their many-body physics in the available geometries of rings and shells and discusses the open research questions.