Vindication for New Bose Gas Theory

One-dimensional systems of interacting particles offer researchers a window into macroscale quantum effects. To simplify analysis of such systems, researchers often treat them as continuous fluids rather than discrete bodies. However, this approach fails if the particles are not in thermal equilibrium. In 2016, researchers proposed a new hydrodynamic framework to solve this conundrum (see 27 December 2006 Viewpoint). Now, experiments show that this theory successfully describes the behavior of a 1D Bose gas as it is released from confinement, promising insights into a whole class of out-of-equilibrium many-body systems.