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.Synthesizing a Sigma circumflex accent z spin-dependent force for optical, metastable, and ground-state trapped-ion qubits
Physical Review A American Physical Society 107:2 (2023) 22617