Engineering fast and stable splitting of matter waves

Abstract

When attempting to split a coherent noninteracting atomic cloud by bifurcating the initial trap into two well-separated wells, slow adiabatic following is unstable with respect to any slight trap asymmetry, and the matter wave "collapses" to the well with the lowest energy. A generic fast chopping splits the wave but it also excites it. Shortcuts to adiabaticity engineered to speed up the unperturbed adiabatic process through nonadiabatic transients provide, instead, quiet and robust balanced splitting. For a Bose-Einstein condensate in the mean-field limit, the interatomic interaction makes the splitting, adiabatic or via shortcuts, more stable with respect to trap asymmetry. Simple formulas are provided to distinguish different regimes.