Abstract We demonstrate key multi-qubit quantum-logic primitives in a dual-species trapped-ion system based on $${}^{40}$$ 40 Ca $${}^{+}$$ + and $${}^{88}$$ 88 Sr $${}^{+}$$ + ions, using two optical qubits with quantum-logic-control frequencies in the red to near-infrared range. With all ionization, cooling, and control wavelengths in a wavelength band similar for the two species and centered in the visible, and with a favorable mass ratio for sympathetic cooling, this pair is a promising candidate for scalable quantum information processing. Same-species and dual-species two-qubit gates, based on the Mølmer–Sørensen interaction and performed in a cryogenic surface-electrode trap, are characterized via the fidelity of generated entangled states; we achieve fidelities of 98.8(2)% and 97.5(2)% in Ca $${}^{+}$$ + –Ca $${}^{+}$$ + and Sr $${}^{+}$$ + –Sr $${}^{+}$$ + gates, respectively. For a similar Ca $${}^{+}$$ + –Sr $${}^{+}$$ + gate, we achieve a fidelity of 94.3(3)%, and carrying out a Sr $${}^{+}$$ + –Sr $${}^{+}$$ + gate performed with a Ca $${}^{+}$$ + sympathetic cooling ion in a Sr $${}^{+}$$ + –Ca $${}^{+}$$

arXiv:1905.13122npj Quantum InformationNov 21, 201949 citations

arXiv:1508.03392 · Nature

Multi-element logic gates for trapped-ion qubits

Ting Rei Tan, John Gaebler, Yiheng Lin, Y. Wan, R. Bowler, Dietrich G. Leibfried, David J. Wineland

Published Dec 15, 2015• 171 citations

arXiv HTML PDF

DOI: 10.1038/nature16186

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arXiv:1905.13122npj Quantum InformationNov 21, 201949 citations

Abstract We demonstrate key multi-qubit quantum-logic primitives in a dual-species trapped-ion system based on

{}^{40}

40 Ca

{}^{+}

+ and

{}^{88}

88 Sr

{}^{+}

+ ions, using two optical qubits with quantum-logic-control frequencies in the red to near-infrared range. With all ionization, cooling, and control wavelengths in a wavelength band similar for the two species and centered in the visible, and with a favorable mass ratio for sympathetic cooling, this pair is a promising candidate for scalable quantum information processing. Same-species and dual-species two-qubit gates, based on the Mølmer–Sørensen interaction and performed in a cryogenic surface-electrode trap, are characterized via the fidelity of generated entangled states; we achieve fidelities of 98.8(2)% and 97.5(2)% in Ca

{}^{+}

+ –Ca

{}^{+}

+ and Sr

{}^{+}

+ –Sr

{}^{+}

+ gates, respectively. For a similar Ca

{}^{+}

+ –Sr

{}^{+}

+ gate, we achieve a fidelity of 94.3(3)%, and carrying out a Sr

{}^{+}

+ –Sr

{}^{+}

+ gate performed with a Ca

{}^{+}

+ sympathetic cooling ion in a Sr

{}^{+}

+ –Ca

{}^{+}