dorsal/arxiv
View SchemaPlasmon-assisted Quantum Entanglement
| Authors | E. Altewischer, M. P. van Exter, J. P. Woerdman |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0203057 |
| URL | https://arxiv.org/abs/quant-ph/0203057 |
| DOI | 10.1038/nature00869 |
| Journal | Nature 418 (2002), 304-306 |
Abstract
The state of a two-particle system is called entangled when its quantum mechanical wave function cannot be factorized in two single-particle wave functions. Entanglement leads to the strongest counter-intuitive feature of quantum mechanics, namely nonlocality. Experimental realization of quantum entanglement is relatively easy for the case of photons; a pump photon can spontaneously split into a pair of entangled photons inside a nonlinear crystal. In this paper we combine quantum entanglement with nanostructured metal optics in the form of optically thick metal films perforated with a periodic array of subwavelength holes. These arrays act as photonic crystals that may convert entangled photons into surface-plasmon waves, i.e., compressive charge density waves. We address the question whether the entanglement survives such a conversion. We find that, in principle, optical excitation of the surface plasmon modes of a metal is a coherent process at the single-particle level. However, the quality of the plasmon-assisted entanglement is limited by spatial dispersion of the hole arrays. This spatial dispersion is due to the nonlocal dielectric response of a metal, which is particularly large in the plasmonic regime; it introduces "which way" labels, that may kill entanglement.
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"abstract": "The state of a two-particle system is called entangled when its quantum\nmechanical wave function cannot be factorized in two single-particle wave\nfunctions. Entanglement leads to the strongest counter-intuitive feature of\nquantum mechanics, namely nonlocality. Experimental realization of quantum\nentanglement is relatively easy for the case of photons; a pump photon can\nspontaneously split into a pair of entangled photons inside a nonlinear\ncrystal. In this paper we combine quantum entanglement with nanostructured\nmetal optics in the form of optically thick metal films perforated with a\nperiodic array of subwavelength holes. These arrays act as photonic crystals\nthat may convert entangled photons into surface-plasmon waves, i.e.,\ncompressive charge density waves. We address the question whether the\nentanglement survives such a conversion. We find that, in principle, optical\nexcitation of the surface plasmon modes of a metal is a coherent process at the\nsingle-particle level. However, the quality of the plasmon-assisted\nentanglement is limited by spatial dispersion of the hole arrays. This spatial\ndispersion is due to the nonlocal dielectric response of a metal, which is\nparticularly large in the plasmonic regime; it introduces \"which way\" labels,\nthat may kill entanglement.",
"arxiv_id": "quant-ph/0203057",
"authors": [
"E. Altewischer",
"M. P. van Exter",
"J. P. Woerdman"
],
"categories": [
"quant-ph"
],
"doi": "10.1038/nature00869",
"journal_ref": "Nature 418 (2002), 304-306",
"title": "Plasmon-assisted Quantum Entanglement",
"url": "https://arxiv.org/abs/quant-ph/0203057"
},
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