Dam-break reflections in a Bose-Einstein condensate*

At ultracold temperatures, atoms in a Bose-Einstein condensate (BEC) exhibit remarkable behaviors, including superfluidity. BECs offer a versatile platform for studying hydrodynamic flow using tunable light fields. In recent work, we quantified the superfluid flow resulting from a dam-break in a harmonic trap, revealing a region where phonon-like excitations are trapped, creating an acoustic white hole. In this project, we build on these studies using a rubidium BEC and a sweeping repulsive optical barrier to investigate dam-reflection dynamics and search for novel phenomena. Our findings show that the sudden release of the condensate from a dam-break initial condition generates a wavefront that accumulates along the barrier. This exploration provides new insights into the dynamic behavior of complex flow profiles in quantum fluids.