Experimental Realization of Wheeler's Delayed-Choice Gedanken Experiment

Abstract

Wave-particle duality is strikingly illustrated by Wheeler's delayed-choice gedanken experiment, where the configuration of a two-path interferometer is chosen after a single-photon pulse has entered it: Either the interferometer is closed (that is, the two paths are recombined) and the interference is observed, or the interferometer remains open and the path followed by the photon is measured. We report an almost ideal realization of that gedanken experiment with single photons allowing unambiguous which-way measurements. The choice between open and closed configurations, made by a quantum random number generator, is relativistically separated from the entry of the photon into the interferometer.

NMR implementation of a quantum delayed-choice experiment

“…That is, the behavior of the photon in the interferometer depends on the choice of the observable that is measured, even when that choice is made at a position and a time such that it is separated from the entrance of the photon into the interferometer by a space-like interval. Breaking the causal link had no effect on the results of the wave-particle duality, thus ruling out the existence of hidden information [15]. More recently, Ionicioiu and Terno have proposed a modified version (Fig.…”

“…This way, there is no causal connection between the selection of the paths by the photon and the presence of BS2. Although initially considered as a 'thought-experiment', this proposal has recently been demonstrated by Jacques et al [15]. In their experimental setup, the second beam-splitter (RBS) was controlled by a random number generator (RNG), that choose to switch the beam-splitter ON or OFF after the photon has already passed through BS1.…”

Event‐by‐event simulation of quantum phenomena

“…Our event-based approach has successfully been used for discrete-event simulations of the single beam splitter and Mach-Zehnder interferometer experiment of Grangier et al [7] (see [8][9][10]), Wheeler's delayed choice experiment of Jacques et al [11] (see [10,12,13]), the quantum eraser experiment of Schwindt et al [14] (see [10,15]), two-beam single-photon interference experiments and the single-photon interference experiment with a Fresnel biprism of Jacques et al [16] (see [10,17]), quantum cryptography protocols (see [18]), the Hanbury Brown-Twiss experiment of Agafonov et al [19] (see [10,20]), universal quantum computation (see [21,22]), Einstein-Podolsky-Rosen-Bohm (EPRB)-type of experiments of Aspect et al [23,24] and Weihs et al [25] (see [5,10,[26][27][28][29][30]), and the propagation of electromagnetic plane waves through homogeneous thin films and stratified media (see [10,31]). An extensive review of the simulation method and its applications is given in [10].…”

An Approach To “Quantumness” In Coherent Control

“…With all the specific attributes of photoelectron spin control, however, repeating such a success would be expremely difficult. Furthermore, we could have discussed far simpler examples of quantum erasure [103,105,145], delayed choice [102,[146][147][148], and quantum delayed choice [51,78,79], based on established technology like linear quantum optics that is used routinely in applications of quantum information theory. Indeed, we do not propose photoelectron spin control to show that quantum erasure and quantum delayed choice are possible or to provide further evidence that nature violates local realism.…”