title: From cosmology to cold atoms: observation of Sakharov oscillations in a quenched atomic superfluid.
abstract: Predicting the dynamics of many-body systems far from equilibrium is a challenging theoretical problem. A long-predicted phenomenon in hydrodynamic nonequilibrium systems is the occurrence of Sakharov oscillations, which manifest in the anisotropy of the cosmic microwave background and the large-scale correlations of galaxies. Here, we report the observation of Sakharov oscillations in the density fluctuations of a quenched atomic superfluid through a systematic study in both space and time domains and with tunable interaction strengths. Our work suggests a different approach to the study of nonequilibrium dynamics of quantum many-body systems and the exploration of their analogs in cosmology and astrophysics.
authors.affiliation: The James Franck Institute and Department of Physics, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Chen-Lung
authors.initials: CL
authors.lastname: Hung
authors.forename: Victor
authors.initials: V
authors.lastname: Gurarie
authors.forename: Cheng
authors.initials: C
authors.lastname: Chin