论文标题
耐故障量子总线体系结构中的远程数据传输
Long-range data transmission in a fault-tolerant quantum bus architecture
论文作者
论文摘要
我们提出了一个在矩形$ r $的矩形阵列的末端的耐故障长距离纠缠生成的方案和一个大小$ d \ times d $的方形横截面，带有$ d = o（\ log log r）$。为了有效地计算的Pauli校正，该方案使用深度为2 $ 6 $的电路产生了最大的纠缠状态，该状态仅由最近的邻居Clifford Gates和本地测量值组成。与现有的量子通信的现有故障耐受性方案相比，该协议的区别在于其低潜伏度：从产品状态开始，纠缠状态是在时间$ o（t _ {\ textrm {local}}} $的时间内准备的，仅由本地栅极和测量操作时间$ t _ {\ textrm {\ textrm {local {local {local {local {local} $ {此外，本地中继器站的要求很小：每个中继器仅使用$θ（\ log^2 r）$ QUBITS，其寿命$ O（t _ {\ textrm {local}}）$。我们证明，在所有低延迟方案中，每个中继器的量子数量汇总了$ω（\ log r）$，用于距离$ r $ $ r $。此外，当量子位在方格中排列时，中继器中的所有操作都是本地的。 我们方案的噪声弥补取决于基础群集状态的断层耐受性。我们提供了完整的误差分析，建立了针对一般（电路级）局部随机噪声影响准备，纠缠操作和测量的局部随机噪声的易屈服阈值。这尤其包括在时间和空间上相关的错误。我们的保守分析估计值令人惊讶地乐观，这表明该方案适用于在近期量子计算设备之间以及之间的远程纠缠产生。
We propose a scheme for fault-tolerant long-range entanglement generation at the ends of a rectangular array of qubits of length $R$ and a square cross section of size $d\times d$ with $d=O(\log R)$. Up to an efficiently computable Pauli correction, the scheme generates a maximally entangled state of two qubits using a depth-$6$ circuit consisting of nearest-neighbor Clifford gates and local measurements only. Compared with existing fault-tolerance schemes for quantum communication, the protocol is distinguished by its low latency: starting from a product state, the entangled state is prepared in a time $O(t_{\textrm{local}})$ determined only by the local gate and measurement operation time $t_{\textrm{local}}$. Furthermore, the requirements on local repeater stations are minimal: Each repeater uses only $Θ(\log^2 R)$ qubits with a lifetime of order $O(t_{\textrm{local}})$. We prove a converse bound $Ω(\log R)$ on the number of qubits per repeater among all low-latency schemes for fault-tolerant quantum communication over distance $R$. Furthermore, all operations within a repeater are local when the qubits are arranged in a square lattice. The noise-resilience of our scheme relies on the fault-tolerance properties of the underlying cluster state. We give a full error analysis, establishing a fault-tolerance threshold against general (circuit-level) local stochastic noise affecting preparation, entangling operations and measurements. This includes, in particular, errors correlated in time and space. Our conservative analytical estimates are surprisingly optimistic, suggesting that the scheme is suited for long-range entanglement generation both in and between near-term quantum computing devices.
