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arXiv · 1808.02555

Entangling an arbitrary pair of qubits in a long ion crystal

Pak Hong Leung·Kenneth R. Brown
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Abstract

It is well established that the collective motion of ion crystals can be used as a quantum bus for multi-qubit entanglement. However, as the number of ions increases, it becomes difficult to directly entangle ions far apart and resolve all motional modes of the ion crystal. We introduce a scalable and flexible scheme for efficient entanglement between any pair of ions within a large ion chain, using an evenly distributed 50-ion crystal as an example. By performing amplitude and frequency modulation, we find high-fidelity pulse sequences that primarily drive a transverse motional mode with a wavelength of 4 ion spacings. We present two $500 μs$ pulses that can in theory suppress gate errors due to residual motion to below $10^{-4}$, and observe a trade-off between gate power and robustness against unwanted frequency offsets.

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Pak Hong Leung, Kenneth R. Brown. 2018-08-07. Entangling an arbitrary pair of qubits in a long ion crystal. https://doi.org/10.1103/physreva.98.032318

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