Delayed choices in atom Stern-Gerlach interferometry

Abstract

Delayed-choice experiments have been performed using an atomic Stern-Gerlach interferometer operating with a low-intensity beam of metastable hydrogen atoms. By use of a fast-commutable analyzer, it is possible to modify the operating mode of the interferometer while the atom has already entered the device. Various types of delayed-choice experiments have been carried out to check the standard interpretation of quantum-mechanics. Within the experimental accuracy, our results do not show any discrepancy between permanent and delayed-choice operating modes of the interferometer. \textcopyright{} 1996 The American Physical Society.