Design of a Quantum Error Correction Decoder Exploiting Temporal Parallelism

In the pursuit of fault-tolerant quantum computing, low-latency quantum error correction (QEC) is essential to prevent rapid error accumulation within the syndrome measurement cycle. In this work, we propose a microarchitecture that implements the sandwich decoding method using the Union-Find algorithm by exploiting temporal parallelism, and we present an ASIC implementation. Through logic synthesis and simulation, we show that the proposed decoder achieves an average latency reduction of 35% at code distance d = 21 compared with a conventional batch Union-Find decoder, while maintaining a comparable logical error threshold of approximately 1.5% under phenomenological noise.