Entangled states of trapped atomic ions

Abstract

To process information using quantum-mechanical principles, the states of individual particles need to be entangled and manipulated. One way to do this is to use trapped, laser-cooled atomic ions. Attaining a general-purpose quantum computer is, however, a distant goal, but recent experiments show that just a few entangled trapped ions can be used to improve the precision of measurements. If the entanglement in such systems can be scaled up to larger numbers of ions, simulations that are intractable on a classical computer might become possible.

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Figure 1: Ions confined in a trap.
Figure 2: A CNOT-gate operation with two trapped ions.
Figure 3: A two-qubit phase gate.
Figure 4: Entanglement produced by conditional measurements.
Figure 5: Measured density matrices of Bell states.
Figure 6: Multizone trap arrays.

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Acknowledgements

We thank H. Häffner, J. Home, E. Knill, D. Leibfried, C. Roos and P. Schmidt for comments on the manuscript.

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Correspondence should be addressed to R.B. (Rainer.Blatt@uibk.ac.at).

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Blatt, R., Wineland, D. Entangled states of trapped atomic ions. Nature 453, 1008–1015 (2008). https://doi.org/10.1038/nature07125

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