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A: Fachverband Atomphysik

A 18: Ultracold atoms II (jointly with Q)

A 18.2: Vortrag

Donnerstag, 13. März 2008, 08:45–09:00, 2F

Slicing a Bose-Einstein Condensate: Direct observation of number squeezing — •Christian Gross, Jerome Esteve, Andreas Weller, Stefano Giovanazzi, and Markus K. Oberthaler — Kirchhoff Institut für Physik, Universität Heidelberg

Todays interferometers are very often limited by the standard quantum limit. Pushing the performance beyond this limit demands the use of number squeezed states.

We report on the direct observation of number squeezed states in Bose-Einstein Condensates (BEC). These are produced by ramping up a one dimensional optical lattice adiabatically, slicing an initially almost pure condensate of ⁸⁷Rb atoms into seven pieces.

Our system can be described as an array of Josephson junctions. The effective interaction between the atoms increases with barrier height and their motion is more and more restricted to single wells since the tunneling coupling across the junctions decreases. In this regime the ground state of the Josephson junction array is characterized by a loss of phase coherence and sub shot noise atom number fluctuations across the junctions.