论文标题
快速逻辑和缓慢的逻辑：在低频磁通上的微波活化的受控-z门
Fast logic with slow qubits: microwave-activated controlled-Z gate on low-frequency fluxoniums
论文作者
论文摘要
我们演示了一个受控的Z门，其电容耦合的Fluxonium Qubits具有过渡频率$ 72.3〜 \ textrm {MHz} $和$ 136.3〜 \ textrm {MHz} $。该大门被$ 61.6〜 \ textrm {ns} $ long Pulse以非计算过渡之间的频率$ | 10 \ rangle- | 20 \ rangle $和$ | 11 \ rangle- | | 21 \ rangle $，在此期间，Qubits仅完成了$ 4 $ $ 4 $和$ 8 $ LARMOR的时期。测得的门误差为$（8 \ pm1）\ times 10^{ - 3} $受到非计算子空间中的折叠的限制，这可能会在下一代设备中改善。尽管我们的Qubits速度比Transmons慢五十倍，但两数Qubit的栅极比TransMons上的微波炉激活门快，并且栅极误差与报告的最低距离相当。低频磁通的建筑优势包括长量子相干时间，计算子空间中的杂交较弱，抑制了残留的$ zz $ - 偶联率（此处为$ 46〜 \ mathrm {kHz} $）以及是否没有过多的参数匹配的参数匹配或复杂的脉搏脉冲或复杂的脉冲型或复杂的脉冲形状要求。
We demonstrate a controlled-Z gate between capacitively coupled fluxonium qubits with transition frequencies $72.3~\textrm{MHz}$ and $136.3~\textrm{MHz}$. The gate is activated by a $61.6~\textrm{ns}$ long pulse at the frequency between non-computational transitions $|10\rangle - |20\rangle$ and $|11\rangle - |21\rangle$, during which the qubits complete only $4$ and $8$ Larmor periods, respectively. The measured gate error of $(8\pm1)\times 10^{-3}$ is limited by decoherence in the non-computational subspace, which will likely improve in the next generation devices. Although our qubits are about fifty times slower than transmons, the two-qubit gate is faster than microwave-activated gates on transmons, and the gate error is on par with the lowest reported. Architectural advantages of low-frequency fluxoniums include long qubit coherence time, weak hybridization in the computational subspace, suppressed residual $ZZ$-coupling rate (here $46~\mathrm{kHz}$), and absence of either excessive parameter matching or complex pulse shaping requirements.
