AI 中文总结
研究利用IBM量子计算机，通过特定编码和操作方案，实现部分容错量子模拟，在估计局部可观测量上优于未编码模拟，还引入新技术提高精度，在1+1D和2+1D模拟中提升可观测量精度。
AI 中文摘要
量子错误检测码为提高有噪声硬件上量子模拟的性能提供了一条近期途径。我们使用IBM的超导量子计算机ibm_boston表明，在估计局部可观测量时，1+1D和2+1D伊辛模型的部分容错编码量子模拟优于未编码的模拟。为在重六边形量子处理器上表示42个逻辑量子比特，使用了21个[[4, 2, 2]]冰山码块和多达136个物理量子比特。通过将容错的综合症提取与非容错逻辑操作配对，该方案保留了许多错误检测的优点，同时避免了完全容错逻辑门集通常所需的开销。编码的方形逻辑连通性以及在每个块内放置逻辑量子比特的自由度，使得能够以比未编码实现更低的电路深度模拟二维空间晶格。我们引入了基于综合症相关性的选择性过滤技术“可观测量排序后选择”，可在不产生完全综合症后选择所带来的大量测量损失的情况下恢复可靠结果。在设备误差的累积影响下，这种编码在1+1D模拟的中间时间将局部可观测量的精度比未编码基线提高了2%-6%，在2+1D模拟的最晚时间随着电路深度增长到超过200%。
英文摘要
Quantum error-detecting codes offer a near-term path for improving the performance of quantum simulations on noisy hardware. Using IBM's superconducting quantum computer ibm_boston, we show that partially fault-tolerant encoded quantum simulations of the Ising model in 1+1D and 2+1D outperform their unencoded counterparts in estimating local observables. To represent 42 logical qubits on the heavy-hex quantum processor, 21 blocks of the [[4, 2, 2]] Iceberg code and up to 136 physical qubits are used. By pairing fault-tolerant syndrome extraction with non-fault-tolerant logical operations, this scheme preserves many of the benefits of error detection while avoiding the overhead typically required for a fully fault-tolerant logical gate set. The encoding's square logical connectivity, together with the freedom to place logical qubits within each block, enables simulations of a 2D spatial lattice with lower circuit depth than the unencoded implementation requires. We introduce Observable-Ranked Postselection, a selective-filtering technique based on syndrome correlations that recovers reliable results without the prohibitive shot loss of full syndrome postselection. Under the cumulative effect of device errors, this encoding improves local-observable accuracy over the unencoded baseline by 2-6% at intermediate times in 1+1D simulations, growing with circuit depth to over 200% in 2+1D at the latest times studied.
Comments42 pages, 23 figures, 11 tables, comments welcome
