Matter wave propagation through microstructured waveguide bends

M.W.J. Bromley, B.D. Esry
(Department of Physics, Kansas State University)

The ability to manipulate ultracold atoms has seen significant progress in recent years. In particular, considerable work has been done on ``atom chips''. To further explore the wave nature of propagation through these microstructures, time-dependent quantum mechanical calculations were performed over a range of parameters close to those accessible by recent experiments. It was found that vortices can be generated --- even in the linear regime --- and can be understood to be a general consequence of wave interference. Here, we focussed on the generation and dynamics of vortices during wavepacket propagation through a simple microstructure: a 180^\circ circular waveguide bend with harmonic transverse confinement. In addition, we performed classical calculations based on Ehrenfest's theorem and compared them to our quantum mechanical results to determine whether classical mechanics can predict the amount of transverse excitation caused by a waveguide bend. This comparison elucidates some limits on the use of classical mechanics for predicting matter wave propagation through microstructures.

This work was supported by the Chemical Sciences, Geosciences and Biosciences Division,
Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

Submitted to DAMOP, May 2004 in Tucson, AZ.

 

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