Many-body dynamical delocalization in a kicked one-dimensional ultracold gas

Contrary to a driven classical system that exhibits chaotic behaviour and diffusive energy growth, a kicked quantum system can exhibit the emergence of dynamical localization, which limits energy absorption and leads to the breakdown of ergodicity(1-4). The evolution of dynamically localized states in the presence of many-body interactions has long remained an open questions(5-7). Here we experimentally study an interacting one-dimensional ultracold gas periodically kicked by a pulsed optical lattice and observe the interaction-driven emergence of dynamical delocalization and many-body quantum chaos. The observed dynamics feature sub-diffusive energy growth over a broad parameter range of interaction and kick strengths. These results shed light on interaction-driven transport phenomena in quantum many-body systems, in a regime where theoretical approaches are extremely challenging and provide conflicting predictions.