  In experiments involving Bose condensed atoms trapped in magnetic bottles,
plugging the hole in the bottle potential with a LASER beam produces a new
potential with two minima, and thus a condensate order parameter (i.e. wave
function) with two maxima. When the trapping potential is removed and the
condensate explodes away from the trap, the two wave function maxima act as two
coherent sources which exhibit amplitude interference. A simplified theoretical
treatment of this experimental effect is provided by considering momentum
distributions.
