FIRST AND 2ND SOUND MODES OF A BOSE-EINSTEIN CONDENSATE IN A HARMONICTRAP

We have calculated the first and second sound modes of a dilute intera cting Bose gas in a spherical trap for temperatures (0.6 < T/T-c < 1.2 ) and for systems with 10(4) to 10(8) particles. The second sound mode s (which exist only below T-c) generally have a stronger temperature d ependence than the first sound modes. The puzzling temperature variati ons of the sound modes near T-c recently observed at JILA in systems w ith 10(3) particles match surprisingly well with those of the first an d second sound modes of much larger systems.