Quantum mechanical which-way experiment with an internal degree of freedom

Konrad Banaszek; Paweł Horodecki; M Karpiński; Czesław Radzewicz

doi:10.1038/ncomms3594

Quantum mechanical which-way experiment with an internal degree of freedom

Abstract

For a particle travelling through an interferometer, the trade-off between the available which-way information and the interference visibility provides a lucid manifestation of the quantum mechanical wave-particle duality. Here we analyse this relation for a particle possessing an internal degree of freedom such as spin. We quantify the trade-off with a general inequality that paints an unexpectedly intricate picture of wave-particle duality when internal states are involved. Strikingly, in some instances which-way information becomes erased by introducing classical uncertainty in the internal degree of freedom. Furthermore, even imperfect interference visibility measured for a suitable set of spin preparations can be sufficient to infer absence of which-way information. General results are illustrated with a proof-of-principle single-photon experiment

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Authors (4)

Konrad Banaszek
- University of Warsaw Faculty of Physics
Paweł Horodecki prof. dr hab.
M Karpiński
- University of Warsaw Faculty of Physics
Czesław Radzewicz
- University of Warsaw Faculty of Physics

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Category:: Articles
Type:: artykuł w czasopiśmie wyróżnionym w JCR
Published in:: Nature Communications no. 4, pages 1 - 7,
ISSN: 2041-1723
Language:: English
Publication year:: 2013
Bibliographic description:: Banaszek K., Horodecki P., Karpiński M., Radzewicz C.: Quantum mechanical which-way experiment with an internal degree of freedom// Nature Communications. -Vol. 4, nr. 2594 (2013), s.1-7
DOI:: Digital Object Identifier (open in new tab) 10.1038/ncomms3594
Verified by:: Gdańsk University of Technology