发表机构
The University of Tokyo; Hon Hai (Foxconn) Research Institute; Tamkang University（东京大学; 鸿海（富士康）研究院; 淡江大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究针对分布式量子计算中的通信成本问题，提出在恒定量子比特开销下逼近纠缠成本下界的方法，对克利福德酉算子可达下界，对非克利福德算子成本至多高出2t个贝尔对。
AI 中文摘要
分布式量子计算通过量子通信连接多个量子处理单元（QPU），以共同执行大规模量子计算。由于每个QPU可用的量子比特数量有限，在保持量子比特开销较小的同时减少量子通信量非常重要。为此，我们研究了一种纠缠辅助模型，其中纠缠消耗作为量子通信成本的度量。在该模型中，对于精确确定性实现，目标双体酉算子的算子施密特秩在量子比特开销不受限制时提供了纠缠成本的一般下界。然而，尚不清楚在恒定量子比特开销下该下界能被多接近地逼近。在这项工作中，我们证明对于每个双体克利福德酉算子，每个QPU最多使用两个辅助量子比特即可达到该下界。此外，对于由精确Clifford+$T$分解指定的非克利福德酉算子，其中$T$计数为$t$，我们构造了具有相同量子比特开销的实现，其纠缠成本最多比该下界高出$2t$个贝尔对。
英文摘要
Distributed quantum computation connects multiple quantum processing units (QPUs) through quantum communication to jointly perform large-scale quantum computations. Since the number of qubits available at each QPU is limited, it is important to reduce quantum communication while keeping the qubit overhead small. To this end, we study an entanglement-assisted model, in which entanglement consumption serves as a measure of quantum communication cost. For exact deterministic implementations in this model, the operator Schmidt rank of the target bipartite unitary provides a general lower bound on entanglement cost when qubit overhead is unrestricted. However, it has remained unclear how closely this bound can be approached with constant qubit overhead. In this work, we show that this lower bound is attainable for every bipartite Clifford unitary using at most two auxiliary qubits per QPU. In addition, for non-Clifford unitaries specified by exact Clifford+$T$ decompositions with $T$-count $t$, we construct implementations with the same qubit overhead whose entanglement cost is at most $2t$ Bell pairs above this lower bound.
Comments15 pages, 6 figures, 1 table
