dorsal/arxiv
View SchemaOn the quantum mechanical nature in liquid NMR quantum computing
| Authors | G L Long, H Y Yan, Y s Li, C C Tu, s J Zhu, D Ruan, Y Sun, J X Tao, H M Chen |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0007077 |
| URL | https://arxiv.org/abs/quant-ph/0007077 |
| Journal | Commun. Theor. Phys. 38, 306-308(2002) |
Abstract
The quantum nature of bulk ensemble NMR quantum computing --the center of recent heated debate, is addressed. Concepts of the mixed state and entanglement are examined, and the data in a 2 qubit liquid NMR quantum computation are analyzed. It is pointed out that the key problem in the current debate is the understanding of entanglement in a mixed state system. The following points are concluded in this Letter: 1)Density matrix describes the "state" of an average particle in an ensemble. It can not describe the state of an individual particle in an ensemble in detail; 2) Entanglement is a property of the wave function of a quantum particle(such as an molecule in a liquid NMR sample). Separability of the density matrix can not be used to measure the entanglement of mixed ensemble; 3)The evolution of states in bulk-ensemble NMR quantum computation is quantum mechanical; 4) The coefficient before the effective pure state density matrix, $\epsilon$, is an measure of the simultaneity of the molecules in an ensemble. It reflects the intensity of the NMR signal and has no significance in quantifying the entanglement in the bulk ensemble NMR system. We conclude that the liquid NMR quantum computation is genuine, not just classical simulations.
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"abstract": "The quantum nature of bulk ensemble NMR quantum computing --the center of\nrecent heated debate, is addressed. Concepts of the mixed state and\nentanglement are examined, and the data in a 2 qubit liquid NMR quantum\ncomputation are analyzed. It is pointed out that the key problem in the current\ndebate is the understanding of entanglement in a mixed state system. The\nfollowing points are concluded in this Letter: 1)Density matrix describes the\n\"state\" of an average particle in an ensemble. It can not describe the state of\nan individual particle in an ensemble in detail; 2) Entanglement is a property\nof the wave function of a quantum particle(such as an molecule in a liquid NMR\nsample). Separability of the density matrix can not be used to measure the\nentanglement of mixed ensemble; 3)The evolution of states in bulk-ensemble NMR\nquantum computation is quantum mechanical; 4) The coefficient before the\neffective pure state density matrix, $\\epsilon$, is an measure of the\nsimultaneity of the molecules in an ensemble. It reflects the intensity of the\nNMR signal and has no significance in quantifying the entanglement in the bulk\nensemble NMR system. We conclude that the liquid NMR quantum computation is\ngenuine, not just classical simulations.",
"arxiv_id": "quant-ph/0007077",
"authors": [
"G L Long",
"H Y Yan",
"Y s Li",
"C C Tu",
"s J Zhu",
"D Ruan",
"Y Sun",
"J X Tao",
"H M Chen"
],
"categories": [
"quant-ph"
],
"journal_ref": "Commun. Theor. Phys. 38, 306-308(2002)",
"title": "On the quantum mechanical nature in liquid NMR quantum computing",
"url": "https://arxiv.org/abs/quant-ph/0007077"
},
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