Entanglement, Complementarity, and Vacuum Fields in Spontaneous Parametric Down-Conversion
- Using two crystals for spontaneous parametric down-conversion in a parallel setup, we observe two-photon interference with high visibility. The high visibility is consistent with complementarity and the absence of which-path information. The observations are explained as the effects of entanglement or equivalently in terms of interfering probability amplitudes and also by the calculation of a second-order field correlation function in the Heisenberg picture. The latter approach brings out explicitly the role of the vacuum fields in the down-conversion at the crystals and in the photon coincidence counting. For comparison, we show that the Hong-Ou-Mandel dip can be explained by the same approach in which the role of the vacuum signal and idler fields, as opposed to entanglement involving vacuum states, is emphasized. We discuss the fundamental limitations of a theory in which these vacuum fields are treated as classical, stochastic fields.
Author details: | Ralf Menzel, Axel HeuerORCiDGND, Peter W. MilonniGND |
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DOI: | https://doi.org/10.3390/atoms7010027 |
ISSN: | 2218-2004 |
Title of parent work (English): | Atoms |
Publisher: | MDPI |
Place of publishing: | Basel |
Publication type: | Article |
Language: | English |
Date of first publication: | 2019/02/19 |
Publication year: | 2019 |
Release date: | 2021/06/21 |
Tag: | Hong-Ou-Mandel effect; complementarity; entanglement; spontaneous parametric down-conversion; vacuum fields |
Volume: | 7 |
Issue: | 1 |
Number of pages: | 14 |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Peer review: | Referiert |
Publishing method: | Open Access / Gold Open-Access |
DOAJ gelistet | |
License (German): | ![]() |
External remark: | Zweitveröffentlichung in der Schriftenreihe Postprints der Universität Potsdam : Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 107 |