dorsal/arxiv
View SchemaDetecting two-party quantum correlations in quantum key distribution protocols
| Authors | Marcos Curty, Otfried Gühne, Maciej Lewenstein, Norbert Lütkenhaus |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0409047 |
| URL | https://arxiv.org/abs/quant-ph/0409047 |
| DOI | 10.1103/PhysRevA.71.022306 |
| Journal | Phys. Rev. A 71, 022306 (2005) |
Abstract
A necessary precondition for secure quantum key distribution (QKD) is that sender and receiver can prove the presence of entanglement in a quantum state that is effectively distributed between them. In order to deliver this entanglement proof one can use the class of entanglement witness (EW) operators that can be constructed from the available measurements results. This class of EWs can be used to provide a necessary and sufficient condition for the existence of quantum correlations even when a quantum state cannot be completely reconstructed. The set of optimal EWs for two well-known entanglement based (EB) schemes, the 6-state and the 4-state EB protocols, has been obtained recently [M. Curty et al., Phys. Rev. Lett. 92, 217903 (2004)]. Here we complete these results, now showing specifically the analysis for the case of prepare&measure (P&M) schemes. For this, we investigate the signal states and detection methods of the 4-state and the 2-state P&M schemes. For each of these protocols we obtain a reduced set of EWs. More importantly, each set of EWs can be used to derive a necessary and sufficient condition to prove that quantum correlations are present in these protocols.
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"abstract": "A necessary precondition for secure quantum key distribution (QKD) is that\nsender and receiver can prove the presence of entanglement in a quantum state\nthat is effectively distributed between them. In order to deliver this\nentanglement proof one can use the class of entanglement witness (EW) operators\nthat can be constructed from the available measurements results. This class of\nEWs can be used to provide a necessary and sufficient condition for the\nexistence of quantum correlations even when a quantum state cannot be\ncompletely reconstructed. The set of optimal EWs for two well-known\nentanglement based (EB) schemes, the 6-state and the 4-state EB protocols, has\nbeen obtained recently [M. Curty et al., Phys. Rev. Lett. 92, 217903 (2004)].\nHere we complete these results, now showing specifically the analysis for the\ncase of prepare\u0026measure (P\u0026M) schemes. For this, we investigate the signal\nstates and detection methods of the 4-state and the 2-state P\u0026M schemes. For\neach of these protocols we obtain a reduced set of EWs. More importantly, each\nset of EWs can be used to derive a necessary and sufficient condition to prove\nthat quantum correlations are present in these protocols.",
"arxiv_id": "quant-ph/0409047",
"authors": [
"Marcos Curty",
"Otfried G\u00fchne",
"Maciej Lewenstein",
"Norbert L\u00fctkenhaus"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.71.022306",
"journal_ref": "Phys. Rev. A 71, 022306 (2005)",
"title": "Detecting two-party quantum correlations in quantum key distribution protocols",
"url": "https://arxiv.org/abs/quant-ph/0409047"
},
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