AutoBraid: A Framework for Enabling Efficient Surface Code Communication in Quantum Computing
AutoBraid: A Framework for Enabling Efficient Surface Code Communication in Quantum Computing
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DOI：
10.1145/3466752.3480072
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Fei Hua;Yan-Hao Chen;Yuwei Jin;Chi Zhang;Ari B. Hayes;Youtao Zhang;E. Zhang
中科院分区：
文献类型：
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作者：
Fei Hua;Yan-Hao Chen;Yuwei Jin;Chi Zhang;Ari B. Hayes;Youtao Zhang;E. Zhang
量子计算机可以使用最强大的经典计算机来解决难以解决的问题。然而，量子比特是反复无常的，容易出错。在量子电路的执行中，有必要主动纠正错误。量子纠错(QEC)码是为了实现容错量子计算而开发的。利用QEC，将一个逻辑电路转换为编码电路。目前对量子电路编译的研究主要集中在具有10-100个量子比特且不具备容错能力的NISQ器件上。本文主要研究容错量子硬件的编译。特别是对基于表面码的QEC的通信并行性进行了优化。表面代码电路的执行涉及对大量纠缠的物理量子比特进行非平凡的几何操作。表面代码中的两个量子比特门被实现为时空中的虚拟“管道”，称为编织路径。编织小路应谨慎布设路线，以避免拥堵。量子比特之间的通信被认为是主要的瓶颈，因为它涉及到调度和搜索量子比特之间的同时路径。我们提供了一个有效调度编织路径的框架。我们发现，对于具有局部并行模式的量子程序，我们的框架保证了最优解，而以前基于贪婪启发式的解不能。此外，我们还对局部并行性分析框架进行了扩展，以解决通信瓶颈问题。在解决了通信瓶颈问题后，我们的框架实现了数量级的改进。
Quantum computers can solve problems that are intractable using the most powerful classical computer. However, qubits are fickle and error prone. It is necessary to actively correct errors in the execution of a quantum circuit. Quantum error correction (QEC) codes are developed to enable fault-tolerant quantum computing. With QEC, one logical circuit is converted into an encoded circuit. Most studies on quantum circuit compilation focus on NISQ devices which have 10-100 qubits and are not fault-tolerant. In this paper, we focus on the compilation for fault-tolerant quantum hardware. In particular, we focus on optimizing communication parallelism for the surface code based QEC. The execution of surface code circuits involves non-trivial geometric manipulation of a large lattice of entangled physical qubits. A two-qubit gate in surface code is implemented as a virtual “pipe” in space-time called a braiding path. The braiding paths should be carefully routed to avoid congestion. Communication between qubits is considered the major bottleneck as it involves scheduling and searching for simultaneous paths between qubits. We provide a framework for efficiently scheduling braiding paths. We discover that for quantum programs with a local parallelism pattern, our framework guarantees an optimal solution, while the previous greedy-heuristic-based solution cannot. Moreover, we propose an extension to the local parallelism analysis framework to address the communication bottleneck. Our framework achieves orders of magnitude improvement after addressing the communication bottleneck.