  In the short wavelength limit the Bogoliubov quasiparticles of trapped
Bose-Einstein condensates can be described as classical particles and
antiparticles with dynamics in a mixed phase-space. For anisotropic parabolic
traps we determine the location of the resonances and study the influence of
the sharpness of the condensate surface on the appearance of chaos as the
energy of the quasiparticles is lowered from values much larger than to values
comparable with the chemical potential.
