D.M. Kurn

Direct, Nondestructive Observation of a Bose Condensate

The spatial observation of a Bose condensate is reported. Dispersive light scattering was used to observe the separation between the condensed and normal components of the Bose gas inside a magnetic trap. This technique is nondestructive, and about a hundred images of the same condensate can be taken. The width of the angular distribution of scattered light increased suddenly at the phase transition.

BOSE-EINSTEIN CONDENSATION OF ULTRACOLD ATOMIC GASES

Bose–Einstein condensation in a dilute gas of sodium atoms has been observed. The atoms were trapped in an optically plugged magnetic trap or in a cloverleaf magnetic trap. Rf induced evaporative cooling increased the phase-space density by six orders of magnitude. We summarize the different techniques used, and discuss recent studies of properties of Bose condensates with an outlook on future developments.

Bose-Einstein condensates—a new form of quantum matter

We review the recent achievements in observing Bose-Einstein condensation (BEC) in magnetically-trapped gases, and summarize our own studies of BEC in sodium. Thermal sodium atoms were optically trapped and cooled and then transferred to a cloverleaf magnetic trap. Radio-frequency induced evaporation increased the phase-space density by six orders of magnitude and condensates with up to ten million atoms were observed. Basic properties of the condensate such as condensate fraction and mean-field energy were found to be in agreement with theory. “Dark-ground” imaging has been used to observe the condensate directly and nondestructively. We have also investigated the low frequency oscillation modes of a condensate, and taken the first steps towards an “atom laser” by demonstrating an rf output coupler for a Bose condensate.

Bose-Einstein Condensation in a Gas of Sodium Atoms

We have observed Bose-Einstein condensation of sodium atoms. The atoms were trapped in a novel trap that employed both magnetic and optical forces. Evaporative cooling increased the phase-space density by 6 orders of magnitude within seven seconds. Condensates contained up to 5 3 105 atoms at densities exceeding 1014 cm23. The striking signature of Bose condensation was the sudden appearance of a bimodal velocity distribution below the critical temperature of , 2 mK. The distribution consisted of an isotropic thermal distribution and an elliptical core attributed to the expansion of a dense condensate.

Bose-Einstein-condensation and prospects for precision measurements

Summary form only given. In the past year, within a few months, three groups have independently succeeded in demonstrating Bose-Einstein condensation (BEC) in a gas of alkali atoms. Our initial experiments, on BEC in sodium, were done in an optically plugged spherical quadrupole trap. Since then, we have developed a dc electromagnetic trap, demonstrated BEC in this trap, and observed light-scattering off the condensate in this trap. The trap is stable, easy to operate, and provides excellent confinement, which is important for efficient and fast production of Bose condensates. These properties are necessary for a detailed study of BEC, and for possible applications of Bose-condensed atoms. In this presentation our results to date will be reviewed. In addition, we will discuss some of the prospects for using Bose condensed atoms for precision measurements.