Verifiable Blind Quantum Computing with Trapped Ions and Single Photons
Physical Review Letters American Physical Society (APS) 132:15 (2024) 150604
Breaking the Entangling Gate Speed Limit for Trapped-Ion Qubits Using a Phase-Stable Standing Wave.
Physical review letters American Physical Society (APS) 131:22 (2023) 220601
Abstract:
All laser-driven entangling operations for trapped-ion qubits have hitherto been performed without control of the optical phase of the light field, which precludes independent tuning of the carrier and motional coupling. By placing ^{88}Sr^{+} ions in a λ=674 nm standing wave, whose relative position is controlled to ≈λ/100, we suppress the carrier coupling by a factor of 18, while coherently enhancing the spin-motion coupling. We experimentally demonstrate that the off-resonant carrier coupling imposes a speed limit for conventional traveling-wave Mølmer-Sørensen gates; we use the standing wave to surpass this limit and achieve a gate duration of 15 μs, restricted by the available laser power.Verifiable blind quantum computing with trapped ions and single photons
ArXiv 2305.02936 (2023)
Robust quantum memory in a trapped-ion quantum network node
Physical Review Letters American Physical Society 130 (2023) 090803
Abstract:
We integrate a long-lived memory qubit into a mixed-species trapped-ion quantum network node. Ion-photon entanglement first generated with a network qubit in 88Sr+ is transferred to 43Ca+ with 0.977(7) fidelity, and mapped to a robust memory qubit. We then entangle the network qubit with another photon, which does not affect the memory qubit. We perform quantum state tomography to show that the fidelity of ion-photon entanglement decays ∼ 70 times slower on the memory qubit. Dynamical decoupling further extends the storage time; we measure an ion-photon entanglement fidelity of 0.81(4) after 10 s.Robust Quantum Memory in a Trapped-Ion Quantum Network Node
ArXiv 2210.11447 (2022)