Elastic scattering losses in the four-wave mixing of Bose Einstein

Marek Trippenbach, Paweł Zin, Jan Chwedeńczuk

Wenji Deng, Shutuan Zhao, Ouyang Jian +1 more

Y. B. Band, Marek Trippenbach, J. P. Burke +1 more

Bragg diffraction of atoms by light waves can create high momentum components in a Bose-Einstein condensate. Collisions between atoms from two distinct momentum wave packets cause elastic scattering that can remove a significant fraction of atoms from the wave packets and cause the formation of a spherical shell of scattered atoms. We develop a slowly varying envelope technique that includes the effects of this loss on the condensate dynamics described by the Gross-Pitaevski equation. Three-dimensional numerical calculations are presented for two experimental situations: passage of a moving daughter condensate through a nonmoving parent condensate, and four-wave mixing of matter waves.

A. Wynveen

Jan Chwedeńczuk, Marek Trippenbach, Kazimierz Rza̧żewski

We introduce a classical stochastic field method that accounts for the quantum fluctuations responsible for spontaneous initiation of various atom optics processes. We assume a delta-correlated Gaussian noise in all initially empty modes of atomic field. Its strength is determined by comparison with the analytical results for two colliding condensates in the low loss limit. Our method is applied to the atomic four wave mixing experiment performed at MIT [Vogels {\it et. al.}, Phys. Rev. Lett. {\bf 89}, 020401, (2002)], for the first time reproducing experimental data.

S. Inouye, A. P. Chikkatur, Dan Stamper-Kurn +3 more