Dipole and multipole traps

C. Champenois, Mathieu Marciante, J. Pedregosa-Gutierrez +1 more

Rob Clark, Timothy Burke, Dylan Green

Mathieu Marciante, C. Champenois, A. Calisti +1 more

Jan Teske, R. Walser

Technical optics with matter waves requires a universal description of three-dimensional traps, lenses, and complex matter-wave fields. In analogy to the two-dimensional Zernike expansion in beam optics, we present a three-dimensional multipole expansion for Bose-condensed matter waves and optical devices. We characterize real magnetic chip traps, optical dipole traps, and the complex matter-wave field in terms of spherical harmonics and radial Stringari polynomials. We illustrate this procedure for typical harmonic model potentials as well as real magnetic and optical dipole traps. Eventually, we use the multipole expansion to characterize the aberrations of a ballistically interacting expanding Bose–Einstein condensate in (3 + 1) dimensions. In particular, we find deviations from the quadratic phase ansatz in the popular scaling approximation. The scheme is data efficient by representing millions of complex amplitudes of a field on a Cartesian grid in terms of a low order multipole expansion without precision loss. This universal multipole description of aberrations can be used to optimize matter-wave optics setups, for example, in matter-wave interferometers.

Galina A. Nemova

Stanley Pau

A technique to trap and separate particle of different dipole moment using a hexapole potential is presented. The operation is similar to the method of ion trap mass spectrometer in that the trajectory of a dipole can be described by Mathieu equation. The technique can also be generalized to trap particle of higher order moment by including higher multipole components in the design of the potential.