Session L36 - General Poster Session II.
POSTER session, Wednesday morning, March 22
Exhibit Hall, MCC
Experimental observations [1,2]of some of the modes of lowest frequency above a Bose condensate in a harmonic trap raises the question whether higher modes might also be observed. A systematic study of various modes would provide valuable diagnostics for the Bose condensate regime and might also provide useful research tools, analogous to atom Rydberg states. Using the Hartree-Fock Bogoliubov equations and discrete variable representation methods [3], as well as perturbation approaches, we have calculated energies as a function of atom number, atom-atom interaction and temperature. For a spherically symmetric trap, we find that asymptotically, the energies approach the bare harmonic oscillator values as 1/sqrt(n), where n is the number of radial nodes. We have begun to address the crucial question of widths, taking into account Landau and Beliaev processes. Our first results, also for spherical symmetry, indicate that as a function of energy, the widths vary somewhat randomly about a slowly decreasing trend. We will discuss means to excite these resonances selectively by off-resonance modulated laser light or by stimulated Raman scattering. 1. D. S. Jin et al. Phys. Rev. Lett. 78, 764 (1997). 2. D. Stamper-Kurn et al., Phys. Rev. Lett. 81, 500 (1998). 3. T. Bergeman et al., abstract this meeting.