dorsal/arxiv
View SchemaRecent Results in Trapped-Ion Quantum Computing
| Authors | D. Kielpinski, A. Ben-Kish, J. Britton, V. Meyer, M. A. Rowe, C. A. Sackett, W. M. Itano, C. Monroe, D. J. Wineland |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0102086 |
| URL | https://arxiv.org/abs/quant-ph/0102086 |
Abstract
We review recent experiments on entanglement, Bell's inequality, and decoherence-free subspaces in a quantum register of trapped \be ions. We have demonstrated entanglement of up to four ions using the technique of M{\o}lmer and S{\o}rensen. This method produces the state |down down> + |up up> for two ions and the state |down down down down> + |up up up up> for four ions. We generate the entanglement deterministically in each shot of the experiment. Measurements on the two-ion entangled state violates Bell's inequality at the $8\sigma$ level. Because of the high detector efficiency of our apparatus, this experiment closes the detector loophole for Bell's inequality measurements for the first time. This measurement is also the first violation of Bell's inequality by massive particles that does not implicitly assume results from quantum mechanics. Finally, we have demonstrated reversible encoding of an arbitrary qubit, originally contained in one ion, into a decoherence-free subspace (DFS) of two ions. The DFS-encoded qubit resists applied collective dephasing noise and retains coherence under ambient conditions 3.6 times longer than does an unencoded qubit. The encoding method, which uses single-ion gates and the two-ion entangling gate, demonstrates all the elements required for two-qubit universal quantum logic.
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"date_created": "2026-03-02T18:01:42.319000Z",
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"abstract": "We review recent experiments on entanglement, Bell\u0027s inequality, and\ndecoherence-free subspaces in a quantum register of trapped \\be ions. We have\ndemonstrated entanglement of up to four ions using the technique of M{\\o}lmer\nand S{\\o}rensen. This method produces the state |down down\u003e + |up up\u003e for two\nions and the state |down down down down\u003e + |up up up up\u003e for four ions. We\ngenerate the entanglement deterministically in each shot of the experiment.\nMeasurements on the two-ion entangled state violates Bell\u0027s inequality at the\n$8\\sigma$ level. Because of the high detector efficiency of our apparatus, this\nexperiment closes the detector loophole for Bell\u0027s inequality measurements for\nthe first time. This measurement is also the first violation of Bell\u0027s\ninequality by massive particles that does not implicitly assume results from\nquantum mechanics. Finally, we have demonstrated reversible encoding of an\narbitrary qubit, originally contained in one ion, into a decoherence-free\nsubspace (DFS) of two ions. The DFS-encoded qubit resists applied collective\ndephasing noise and retains coherence under ambient conditions 3.6 times longer\nthan does an unencoded qubit. The encoding method, which uses single-ion gates\nand the two-ion entangling gate, demonstrates all the elements required for\ntwo-qubit universal quantum logic.",
"arxiv_id": "quant-ph/0102086",
"authors": [
"D. Kielpinski",
"A. Ben-Kish",
"J. Britton",
"V. Meyer",
"M. A. Rowe",
"C. A. Sackett",
"W. M. Itano",
"C. Monroe",
"D. J. Wineland"
],
"categories": [
"quant-ph"
],
"title": "Recent Results in Trapped-Ion Quantum Computing",
"url": "https://arxiv.org/abs/quant-ph/0102086"
},
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