Published in
Conference on Coherence and Quantum Optics
American Association for the Advancement of Science, Science, 5814(315), p. 966-968, 2007
2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference
DOI: 10.1109/cleoe-iqec.2007.4386903
Links
- Crossref
- American Association for the Advancement of Science
- ORCID
- Institute of Electrical and Electronics Engineers
- [hal.archives-ouvertes.fr] | PDF
- [cds.cern.ch]
- [arxiv.org] | PDF
- [cds.cern.ch] | PDF
- [hal.archives-ouvertes.fr] | PDF
- [arxiv.org] | PDF
- [www.researchgate.net] | PDF
- [arxiv.org] | PDF
- [citeseerx.ist.psu.edu] | PDF
Tools
Experimental Realization of Wheeler's Delayed-Choice Gedanken Experiment
,
Alain Aspect,
Philippe Grangier,
Jean-François Roch
Abstract
The quantum "mystery which cannot go away" (in Feynman's words) of wave-particle duality is illustrated in a striking way by Wheeler's delayed-choice GedankenExperiment. In this experiment, the configuration of a two-path interferometer is chosen after a single-photon pulse has entered it : either the interferometer is \textit{closed} (\textit{i.e.} the two paths are recombined) and the interference is observed, or the interferometer remains \textit{open} and the path followed by the photon is measured. We report an almost ideal realization of that GedankenExperiment, where the light pulses are true single photons, allowing unambiguous which-way measurements, and the interferometer, which has two spatially separated paths, produces high visibility interference. The choice between measuring either the 'open' or 'closed' configuration is made by a quantum random number generator, and is space-like separated -- in the relativistic sense -- from the entering of the photon into the interferometer. Measurements in the closed configuration show interference with a visibility of 94%, while measurements in the open configuration allow us to determine the followed path with an error probability lower than 1%.