Experimental demonstration of high fidelity ${}^{133}$ Ba $^+$ hyperfine qubitsExperimental demonstration of high fidelity ${}^{133}$Ba$^+$ hyperfine qubits

David Hucul, Justin Christensen, Eric R. Hudson +1 more

Bulletin of the American Physical SocietyMay 29, 20180 citations

Experimental realization of ultra-high fidelity qubit operations with tunable fluxonium qubits

Tenghui Wang, Jin Qin, Hao Deng +22 more

Bulletin of the American Physical SocietyMar 17, 20210 citations

High-fidelity operation of a radioactive trapped-ion qubit, $^{133}$ Ba $^+$ High-fidelity operation of a radioactive trapped-ion qubit, $^{133}$Ba$^+$

Justin Christensen

$^{133}$ Ba $^+$ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1/2 nucleus, visible wavelength electronic transitions, and long D-state lifetimes ($\\tau\\sim $1~min). Using a microgram source of radioactive material, we trap and laser-cool the synthetic \\textit{A} = 133 radioisotope of barium II ($ \\tau_{1/2} \\approx 10.5 $~yr) in a radio-frequency ion trap. To demonstrate high fidelity qubit operations, a number of unknown state energies were needed. We measure the isotope shift and hyperfine structure of the 6$ ^2 $P$ _{1/2}\\leftrightarrow 5^2 $D$ _{3/2}$ electronic transition needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. For high-fidelity operations with electron shelving, we report measurements of the 6 $^2$ P $_{3/2}$ and $5^2$ D $_{5/2}$ hyperfine splittings, as well as the~6 $^2$ P $_{3/2}~\\leftrightarrow~6^2$ S $_{1/2}$ and ~6 $^2$ P $_{3/2}~\\leftrightarrow~5^2$ D $_{5/2}$ transition frequencies. Using these transitions, we demonstrate high-fidelity \\ba \\ hyperfine qubit manipulation with electron shelving detection to benchmark qubit state preparation and measurement (SPAM). Using single-shot, threshold discrimination, we measure an average SPAM fidelity of $\\mathcal{F} = 0.99971(3)$ , a factor of $\\approx$ 2 improvement over the best reported performance of any qubit.Finally, we report the 6 $^2$ P $_{1/2}\\leftrightarrow 5^2$ D $_{3/2}$ electronic transition isotope shift for the rare \\textit{A} = 130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes.$^{133}$Ba$^+$ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1/2 nucleus, visible wavelength electronic transitions, and long D-state lifetimes ($\\tau\\sim $1~min). Using a microgram source of radioactive material, we trap and laser-cool the synthetic \\textit{A} = 133 radioisotope of barium II ($\\tau_{1/2} \\approx 10.5$~yr) in a radio-frequency ion trap. To demonstrate high fidelity qubit operations, a number of unknown state energies were needed. We measure the isotope shift and hyperfine structure of the 6$^2$P$_{1/2}\\leftrightarrow 5^2$D$_{3/2}$ electronic transition needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. For high-fidelity operations with electron shelving, we report measurements of the 6$^2$P$_{3/2}$ and $5^2$D$_{5/2}$ hyperfine splittings, as well as the~6$^2$P$_{3/2}~\\leftrightarrow~6^2$S$_{1/2}$ and ~6$^2$P$_{3/2}~\\leftrightarrow~5^2$D$_{5/2}$ transition frequencies. Using these transitions, we demonstrate high-fidelity \\ba \\ hyperfine qubit manipulation with electron shelving detection to benchmark qubit state preparation and measurement (SPAM). Using single-shot, threshold discrimination, we measure an average SPAM fidelity of $\\mathcal{F} = 0.99971(3)$, a factor of $\\approx$ 2 improvement over the best reported performance of any qubit.Finally, we report the 6$^2$P$_{1/2}\\leftrightarrow 5^2$D$_{3/2}$ electronic transition isotope shift for the rare \\textit{A} = 130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes.

Jan 1, 20203 citations

Preparation and detection of a $^{137}$ Ba $^{+}$ hyperfine qubitPreparation and detection of a $^{137}$Ba$^{+}$ hyperfine qubit

Matthew Dietrich, R. Bowler, Nathan Kurz +5 more

Bulletin of the American Physical SocietyMay 28, 20080 citations

Efficient quantum frequency conversion of ultra-violet single photons from a trapped ytterbium ion

Seungwoo Yu, Kyungmin Lee, Sumin Park +4 more

Ion trap system is a leading candidate for quantum information science benefitting from its long coherence time, high-fidelity gate operations. In addition, the ion photon entanglement provides a versatile tool to realize quantum networks by generating an ideal pair of a stationary memory qubit and a flying communication qubit. Rapid developments in nonlinear quantum frequency conversion techniques have enhanced the potential for constructing a trapped ion quantum network via optical fiber connections. The generation of long-distance entanglement has been demonstrated with ions such as Ca+ and Ba+, which emit photons in visible or near-infrared range naturally. On the other hand, as the qubit-native photons reside in ultra-violet (UV) spectrum, the Yb+ ion has not been considered as a strong competitor for telecommunication qubits despite extensive research on it. Here, we demonstrate an efficient difference-frequency conversion of UV photons, emitted from a trapped Yb+ ion, into a visible range. We provide experimental evidence that confirms the converted photons are radiated from the Yb+ ion. Our results provide a crucial step toward realizing a long-distance trapped ion quantum network based on Yb+ ions through quantum frequency conversion.Ion trap system is a leading candidate for quantum information science benefitting from its long coherence time, high-fidelity gate operations. In addition, the ion photon entanglement provides a versatile tool to realize quantum networks by generating an ideal pair of a stationary memory qubit and a flying communication qubit. Rapid developments in nonlinear quantum frequency conversion techniques have enhanced the potential for constructing a trapped ion quantum network via optical fiber connections. The generation of long-distance entanglement has been demonstrated with ions such as Ca+ and Ba+, which emit photons in visible or near-infrared range naturally. On the other hand, as the qubit-native photons reside in ultra-violet (UV) spectrum, the Yb+ ion has not been considered as a strong competitor for telecommunication qubits despite extensive research on it. Here, we demonstrate an efficient difference-frequency conversion of UV photons, emitted from a trapped Yb+ ion, into a visible range. We provide experimental evidence that confirms the converted photons are radiated from the Yb+ ion. Our results provide a crucial step toward realizing a long-distance trapped ion quantum network based on Yb+ ions through quantum frequency conversion.

arXiv:2502.09068Applied Physics LettersFeb 24, 20253 citations

Demonstration of an optical qubit in $^{137}$ Ba $^{+}$ ionsDemonstration of an optical qubit in $^{137}$Ba$^{+}$ ions

Thomas Noël, Matt Dietrich, Nathan Kurz +2 more

Bulletin of the American Physical SocietyMay 27, 20100 citations

Ultra-High Fidelity Operation of the

^{133}

^+

qubit

Experimental demonstration of high fidelity

{}^{133}

^+

hyperfine qubits

High-fidelity operation of a radioactive trapped-ion qubit,

^{133}

^+

^{133}

^+

has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1/2 nucleus, visible wavelength electronic transitions, and long D-state lifetimes ($\\tau\\sim

1~min). Using a microgram source of radioactive material, we trap and laser-cool the synthetic \\textit{A} = 133 radioisotope of barium II (

\\tau_{1/2} \\approx 10.5

~yr) in a radio-frequency ion trap. To demonstrate high fidelity qubit operations, a number of unknown state energies were needed. We measure the isotope shift and hyperfine structure of the 6

P

_{1/2}\\leftrightarrow 5^2

D

_{3/2}$ electronic transition needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. For high-fidelity operations with electron shelving, we report measurements of the 6

^2

_{3/2}

and

5^2

_{5/2}

hyperfine splittings, as well as the~6

^2

_{3/2}~\\leftrightarrow~6^2

_{1/2}

and ~6

^2

_{3/2}~\\leftrightarrow~5^2

_{5/2}

transition frequencies. Using these transitions, we demonstrate high-fidelity \\ba \\ hyperfine qubit manipulation with electron shelving detection to benchmark qubit state preparation and measurement (SPAM). Using single-shot, threshold discrimination, we measure an average SPAM fidelity of

\\mathcal{F} = 0.99971(3)

, a factor of

\\approx

2 improvement over the best reported performance of any qubit.Finally, we report the 6

^2

_{1/2}\\leftrightarrow 5^2

_{3/2}

electronic transition isotope shift for the rare \\textit{A} = 130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes.

Preparation and detection of a

^{137}

^{+}

hyperfine qubit

Demonstration of an optical qubit in

^{137}

^{+}

ions