Squeezed states in a Bose-Einstein condensate

We report manipulation of the atom number statistics associated with Bose-E instein condensed atoms confined in an array of weakly Linked mesoscopic tr aps. We used the interference of atoms released from the traps as a sensiti ve probe of these statistics. By controlling relative strengths of the tunn eling rate between traps and atom-atom interactions within each trap, we ob served trap states characterized by sub-Poissonian number fluctuations and adiabatic transitions between these number-squeeled states and coherent sta tes of the atom field. The quantum states produced in this work may enable substantial gains in sensitivity for atom interference-based instruments as well as fundamental studies of quantum phase transitions.