论文标题
快速，保留终身的读数
Fast, Lifetime-Preserving Readout for High-Coherence Quantum Annealers
论文作者
论文摘要
我们首次证明了量子通量参数元（QFP）能够在电容性分流磁通量值（CSFQ）的读取电路中充当隔离器和放大器。通过将QFP视为可调的耦合器并将其偏置以使耦合的关闭，我们表明，CSFQ的$ T_1 $不受其低Q读出谐振器（$ Q_E = 760美元）的purcell损失的影响，尽管仅被$ 40 $ 40 $ MHz失调。退火后，QFP放大了值的持续电流信号，以使其在读取谐振器中产生$ 85 $ MHz的通量Qubit-State依赖性频移（其$ 9 $ $ 9 $乘以其线宽）。该设备被证明可以在持续的当前基础上读取通量Qubit，忠诚度超过$ 98.6 \％$，只有$ 80 $ NS集成，并以$ 1 $ $ $ $ $ s的整合时达到$ 99.6 \％$。速度和隔离的组合对于读出高碳量子退火器至关重要。
We demonstrate, for the first time, that a quantum flux parametron (QFP) is capable of acting as both isolator and amplifier in the readout circuit of a capacitively shunted flux qubit (CSFQ). By treating the QFP like a tunable coupler and biasing it such that the coupling is off, we show that $T_1$ of the CSFQ is not impacted by Purcell loss from its low-Q readout resonator ($Q_e = 760$) despite being detuned by only $40$ MHz. When annealed, the QFP amplifies the qubit's persistent current signal such that it generates a flux qubit-state-dependent frequency shift of $85$ MHz in the readout resonator, which is over $9$ times its linewidth. The device is shown to read out a flux qubit in the persistent current basis with fidelities surpassing $98.6\%$ with only $80$ ns integration, and reaches fidelities of $99.6\%$ when integrated for $1$ $μ$s. This combination of speed and isolation is critical to the readout of high-coherence quantum annealers.
