Journal article

Lecture demonstrations of interference and quantum erasing with single photons

  • Dimitrova, Todorka Lulcheva University of Plovdiv "Paissi Hilendarski", Plovdiv, Bulgaria - Physics Department, University of Fribourg, Switzerland
  • Weis, Antoine Physics Department, University of Fribourg, Switzerland
Published in:
  • Physica Scripta. - 2009, vol. T135, p. 014003
English Single-photon interference is a beautiful manifestation of the wave–particle duality of light and the double-slit Gedankenexperiment is a standard lecture example for introducing quantum mechanical reality. Interference arises only if each photon can follow several (classical) paths from the source to the detector, and if one does not have the possibility to determine which specific path the photon has taken. Attaching a specific label to the photon traveling along a specific path destroys the interference. However, in some cases those labels can be erased from the photon between leaving the apparatus and being detected, by which interference can be restored, a phenomenon called quantum erasing. We present lecture demonstration experiments that illustrate the wave–particle duality of light and the phenomenon of quantum erasing. Both experiments are first shown with strong light and, in a second step, on a photon-by-photon basis. The smooth transition from the quantum to the classical case can be shown in real time by varying the incident light intensity.
Faculté des sciences et de médecine
Département de Physique
  • English
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