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Spin-dependent forces on trapped ions for phase-stable quantum gates and motional Schrodinger-cat states

P. C. Haljan·K. -A. Brickman·L. Deslauriers·P. J. Lee·C. Monroe
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Abstract

Favored schemes for trapped-ion quantum logic gates use bichromatic laser fields to couple internal qubit states with external motion through a "spin-dependent force." We introduce a new degree of freedom in this coupling that reduces its sensitivity to phase decoherence. We demonstrate bichromatic spin-dependent forces on a single trapped $^{111}$Cd$^+$ ion, and show that phase coherence of the resulting "Schrödinger-cat" states of motion depends critically upon the spectral arrangement of the optical fields. This applies directly to the operation of entangling gates on multiple ions.

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P. C. Haljan, K. -A. Brickman, L. Deslauriers, P. J. Lee, C. Monroe. 2004-11-09. Spin-dependent forces on trapped ions for phase-stable quantum gates and motional Schrodinger-cat states. https://doi.org/10.1103/physrevlett.94.153602

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