For the past two decades harmonically trapped ultracold atomic gases have been used with great success to study fundamental many-body physics in a flexible experimental setting. Recently, we achieved the first atomic Bose-Einstein condensate (BEC) in an essentially uniform potential of an optical-box trap , which has opened new possibilities for closer connections with condensed-matter systems, and theories of the many-body problem that generally rely on the translational symmetry of the system.
In this talk, I will present a study where we drive our uniform BEC out of equilibrium with an oscillating force that pumps energy into the system at the largest length scale . In the limit of weak drives, the BEC’s response is linear, well captured by its lowest-lying excitations. For stronger drives, a nonlinear response is apparent and we observe a gradual development of a turbulent cascade characterized by an isotropic power-law distribution in momentum space. Our conclusions are well supported by comparison with numerical simulations of the Gross-Pitaevskii equation.
 A. L. Gaunt et al., Phys. Rev. Lett. 110, 200406 (2013)
 N. Navon et al., Nature 539, 72 (2016)