Double-slit experiment
Article
The double-slit experiment is a foundational demonstration that light and matter can display behaviour associated with both waves and particles. When a coherent beam passes through two narrow openings, the resulting waves overlap and create an interference pattern of alternating bright and dark regions.
When the experiment is performed at very low intensity, photons, electrons, atoms, or molecules arrive at the detector as individual, localised events. As many events accumulate, their distribution builds the same interference pattern predicted by wave behaviour.
Adding a measurement that determines which slit a particle passes through removes or reduces the interference. The experimental arrangement therefore affects which aspects of the quantum system can be observed, illustrating complementarity and the role of measurement.
The experiment was developed from Thomas Young's early nineteenth-century work on light and was later extended to electrons and larger particles. It remains central to quantum mechanics because classical wave or particle models alone cannot account for all the observed results.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Double-slit_experiment