论文标题
三量量子点旋转Qubits中的全渗透动力脱钩
Full-permutation dynamical decoupling in triple-quantum-dot spin qubits
论文作者
论文摘要
硅中自旋速度的动力脱钩可以增强保真度，并用于提取噪声过程的频谱。我们展示了一种全透明的动力脱钩技术，该技术周期性地交换了三个点量子的旋转。该序列不仅抑制了低频电荷 - 噪声和磁通诱导的误差；它还将泄漏错误重新集中到一阶，这对于仅编码的仅交换Qubits特别有趣。对于我们称为NZ1Y的特定结构，将量子隔离为从错误来源隔离到这样的程度，以至于我们测量出色的交换脉冲错误$ 5 \ times10^{ - 5} $。该序列维持大约18,000个交换脉冲的量子状态，将量子相干性从$ t_2^*= 2〜μ $ s扩展到$ t_2 = 720〜μ $ s。我们在实验上验证了一个错误模型，该模型包括$ 1/f $电荷噪声和$ 1/f $磁噪声，分为两种方式：通过直接交换量模拟，以及通过将假定的噪声光谱与派生的滤波器功能集成在一起，这两者都会重现测得的误差和相对于更改重复率的泄漏。
Dynamical decoupling of spin qubits in silicon can enhance fidelity and be used to extract the frequency spectra of noise processes. We demonstrate a full-permutation dynamical decoupling technique that cyclically exchanges the spins in a triple-dot qubit. This sequence not only suppresses both low frequency charge-noise- and magnetic-noise-induced errors; it also refocuses leakage errors to first order, which is particularly interesting for encoded exchange-only qubits. For a specific construction, which we call NZ1y, the qubit is isolated from error sources to such a degree that we measure a remarkable exchange pulse error of $5\times10^{-5}$. This sequence maintains a quantum state for roughly 18,000 exchange pulses, extending the qubit coherence from $T_2^*=2~μ$s to $T_2 = 720~μ$s. We experimentally validate an error model that includes $1/f$ charge noise and $1/f$ magnetic noise in two ways: by direct exchange-qubit simulation, and by integration of the assumed noise spectra with derived filter functions, both of which reproduce the measured error and leakage with respect to changing the repetition rate.
