title: Long phase coherence time and number squeezing of two Bose-Einstein condensates on an atom chip.
abstract: We measure the relative phase of two Bose-Einstein condensates confined in a radio frequency induced double-well potential on an atom chip. We observe phase coherence between the separated condensates for times up to approximately 200 ms after splitting, a factor of 10 longer than the phase diffusion time expected for a coherent state for our experimental conditions. The enhanced coherence time is attributed to number squeezing of the initial state by a factor of 10. In addition, we demonstrate a rotationally sensitive (Sagnac) geometry for a guided atom interferometer by propagating the split condensates.
authors.affiliation: MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: G-B
authors.initials: GB
authors.lastname: Jo
authors.forename: Y
authors.initials: Y
authors.lastname: Shin
authors.forename: S
authors.initials: S
authors.lastname: Will
authors.forename: T A
authors.initials: TA
authors.lastname: Pasquini
authors.forename: M
authors.initials: M
authors.lastname: Saba
authors.forename: W
authors.initials: W
authors.lastname: Ketterle
authors.forename: D E
authors.initials: DE
authors.lastname: Pritchard
authors.forename: M
authors.initials: M
authors.lastname: Vengalattore
authors.forename: M
authors.initials: M
authors.lastname: Prentiss