Konstanz 1998 – wissenschaftliches Programm

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PV: Plenarvorträge

PV I

PV I: Plenarvortrag

Montag, 16. März 1998, 09:00–09:45, Audimax

Bose-Einstein condensation in an ultracold gas: Recent surprises and new directions — •C. Wieman — University of Colorado, Boulder, USA

We have studied Bose-Einstein condensation in a dilute vapor of rubidium atoms cooled to well below 1 microKelvin. This was achieved by laser cooling and trapping of the atoms, followed by magnetic trapping and evaporative cooling. I will discuss the experiment and the various properties of this novel macroscopic quantum system that we have studied recently. These include collective excitations, collision processes in condensates, and the simultaneous creation and interaction of two different condensates.

By perturbing the condensate we are able to excite and study the frequency and damping of phonon-like excitations. Dramatic and unexpected temperature dependencies in both of these quantities were observed. Also, we have found that the predominant loss processes for condensates is three body recombination, and measurements of this rate probe the higher order coherence of the condensates. Finally, we have developed new techniques for producing coherent and incoherent mixtures of condensates in different spin states, and we are studying their interactions.