Excitations of Trapped Bose condensates

T. Kimura, Hiroki Saito, Masahito Ueda

Li You, R. L. Walsworth, William Hoston

We investigate theoretically the collective excitations of trapped Bose condensates with energies of the order of the chemical potential of the system. For the MIT sodium Bose condensate in a Cloverleaf trap, we find interesting level crossing behavior for high energy excitations and calculate the spatial magnetic dipole moments for selective creation of condensate excitations.

Patrik Öhberg, E.L. Surkov, Ilkka Juhani Tittonen +3 more

M.‐O. Mewes, Michael R. Andrews, N. J. van Druten +4 more

Collective excitations of a dilute Bose condensate have been observed. These excitations are analogous to phonons in superfluid helium. Bose condensates were created by evaporatively cooling magnetically trapped sodium atoms. Excitations were induced by a modulation of the trapping potential, and detected as shape oscillations in the freely expanding condensates. The frequencies of the lowest modes agreed well with theoretical predictions based on mean-field theory. Before the onset of Bose-Einstein condensation, we observed sound waves in a dense ultracold gas.

Mark Edwards

Zbyszek P. Karkuszewski, Krzysztof Sacha, Jakub Zakrzewski

It is shown that by a modification of the trapping potential one may excite Bose-Einstein condensate to a state in which atomic external degrees of freedom are predominantly in the {\\it excited} trap state. Such an excited condensate can be prepared experimentally --- it requires only a proper change in time of the potential in atomic traps, as realized in laboratories already.