We investigate the nonlinear coupling between the lowest three scissors modes of a Bose-Einstein condensate at zero temperature. Using a variational approach with a general variational wave function we determine, solely from the parity of the scissors modes, the nonvanishing coupling terms. In agreement with a similar previous calculation with a Gaussian variational wave function, which is a special case of our general function, we find two resonance conditions at trap anisotropy ratios λ = 1 and λ = √7. We use the latter condition to explain the observed resonance in the collisional damping of scissors modes. In addition, we investigate the higher order scissors modes and the eigenmodes and eigenfrequencies for isotropic traps.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics