title: Revealing single-trap condensate fragmentation by measuring density-density correlations after time of flight.
abstract: We consider ultracold bosonic atoms in a single trap in the Thomas-Fermi regime, forming many-body states corresponding to stable macroscopically fragmented two-mode condensates. It is demonstrated that upon free expansion of the gas, the spatial dependence of the density-density correlations at late times provides a unique signature of fragmentation. This hallmark of fragmented condensate many-body states in a single trap is due to the fact that the time of flight modifies the correlation signal such that two opposite points in the expanding cloud become uncorrelated, in distinction to a nonfragmented Bose-Einstein condensate, where they remain correlated.
authors.affiliation: Department of Physics and Astronomy, Center for Theoretical Physics, Seoul National University, 151-747 Seoul, Korea.
authors.forename: Myung-Kyun
authors.initials: MK
authors.lastname: Kang
authors.affiliation: Department of Physics and Astronomy, Center for Theoretical Physics, Seoul National University, 151-747 Seoul, Korea.
authors.forename: Uwe R
authors.initials: UR
authors.lastname: Fischer