Science 339, 52. The original author arXiv record gives Simon Braun and collaborators, submitted 2 November 2012; the journal year is 2013.
Inspected original author abstract: tailored Bose-Hubbard Hamiltonian, attractively interacting ultracold bosons and sharp quasi-momentum peaks at the upper band edge. PDF retrieval timed out; only the verified abstract is used, with no uninspected apparatus details or historical-priority claims.