Core Insights - The Tokyo University of Science team has made significant advancements in quantum error correction technology by developing an efficient and scalable quantum Low-Density Parity-Check (LDPC) error-correcting code that maintains high stability in systems with hundreds of thousands of logical qubits, approaching theoretical limits [1][2] - This breakthrough provides crucial technical support for achieving large-scale fault-tolerant quantum computing, potentially accelerating practical applications in quantum chemistry, cryptanalysis, and complex optimization [1] Group 1 - The current quantum computers can manipulate dozens of qubits, but solving real-world problems often requires millions of stable and reliable logical qubits [1] - Existing quantum error correction methods generally suffer from high resource consumption and low efficiency, requiring many physical qubits to encode a small number of logical qubits, which severely limits system scalability [1] - Many existing error correction codes have low coding rates and limited performance improvement potential, with significant gaps remaining from the theoretical optimal error correction limit known as the hashing bound [1] Group 2 - The team successfully overcame these challenges by proposing a new construction method that designs prototype LDPC codes with excellent error correction characteristics and introduces affine arrangement-based techniques to enhance code structure diversity [2] - Unlike traditional LDPC codes defined over binary finite fields, the new approach uses non-binary finite fields, allowing each encoding unit to carry more information and thus improving overall error correction capability [2] - The team transformed these prototype codes into a CSS-type quantum error correction code and developed an efficient joint decoding strategy that can simultaneously handle bit-flip and phase-flip errors, unlike most previous methods that could only correct one type at a time [2] Group 3 - Through large-scale numerical simulations, the new error correction code achieves a bit error rate of 10^-4 in systems with hundreds of thousands of logical qubits, with performance very close to the hashing bound [2] - Importantly, the computational complexity required for decoding is proportional to the number of physical qubits, meaning that as system size increases, the resource overhead grows linearly, indicating good engineering feasibility [2]

日本东京科学大学团队在量子纠错技术方面取得重要突破：开发出一种高效且可扩展的量子低密度奇偶 校验（LDPC）纠错码，在包含数十万个逻辑量子比特的系统中仍保持极高的稳定性，性能接近理论界 限。这一成果为实现大规模容错量子计算提供了关键技术支撑，有望推动量子计算机在量子化学、密码 分析和复杂优化等领域的实际应用。 目前，量子计算机已能操控数十个量子比特，但要解决具有现实意义的问题，往往需要数百万甚至更多 稳定可靠的逻辑量子比特。由于量子态极为脆弱，易受到环境干扰而产生错误，且错误会随系统规模扩 大而迅速累积，因此必须依赖高效的纠错机制来维持计算的准确性。然而，现有的量子纠错方法普遍存 在资源消耗大、效率低的问题，通常需用大量物理量子比特编码出少量逻辑量子比特，严重制约了系统 的扩展能力。 更深层次的挑战在于，许多现有纠错码存在编码率低、性能提升空间有限等问题。此外，在高精度运行 区域常出现性能停滞，与理论上可达到的最佳纠错极限——即哈希界限，仍有较大差距。同时，多数方 案在完成主解码后还需进行复杂的后续处理，进一步增加了运算负担。 （文章来源：科技日报） 此次团队成功克服了这些难题。他们提出了一种新的构造方法，首 ...