AI 中文总结
研究以服务器为中心的量子数据中心架构扩展时的问题，通过端到端纯化研究路径多样性与保真度关系，提出HI-QDC架构，该架构能将端到端纠缠转化为有效资源，实现递归可扩展的量子数据中心网络。
AI 中文摘要
以服务器为中心的量子数据中心架构通过在量子处理单元（QPU）之间分配通信任务来实现可扩展性，而非将复杂性集中在中央交换核心。然而，扩展此类架构会增加路径长度、贝尔态测量次数以及端到端保真度的损失。我们探讨以服务器为中心的拓扑结构的路径多样性能否转化为一种不仅能保持速率，还能保持保真度的机制。我们通过端到端纯化作为保真度恢复机制来研究这一问题。首先，在黑箱模型中，我们确定纯化恢复与基本链路匹配的单个副本时必须消耗的原始端到端维纳态副本的最小数量，比较递归2对1和优化的嵌套r对1纯化。其次，我们在概率性BCube架构中实例化这些要求，其边不相交路径多样性提供原始副本。由于纯化对输入保真度有下限要求，没有路径冗余能将输出提高到该阈值以上，这限制了扩展。为解决此问题，我们提出了Hop-Independent Quantum Data Center（HI-QDC），这是一种等距、模块化、可扩展的架构，其中纯化将模块间的端到端纠缠转化为模块间拓扑结构的有效链路级资源。我们的结果确定了在端到端纯化下，BCube模块保持基本链路保真度和产量的条件。该模块随后隐藏其内部跳数，并作为更高级别网络的有效基本链路。因此，拓扑结构提供了纯化所需的路径多样性，而纯化将其转化为保真度恢复，实现了递归可扩展的量子数据中心网络。
英文摘要
Server-centric quantum data-center architectures offer scalability by distributing communication tasks across QPUs rather than concentrating complexity in a centralized switching core. However, scaling such architectures increases the path length, the number of Bell-state measurements, and the loss of end-to-end fidelity. We ask whether the path diversity of a server-centric topology can be converted into a mechanism for preserving not only rate, but also fidelity. We study this through end-to-end purification as a fidelity-restoration mechanism. First, in a black-box model, we determine the minimum number of raw end-to-end Werner-state copies, each carrying the degraded Werner parameter of a distance-ell path, that purification must consume to recover a single copy matching an elementary link, comparing recursive 2-to-1 and optimized nested r-to-1 purification. Second, we instantiate these requirements in a probabilistic BCube architecture, whose edge-disjoint path diversity supplies the raw copies. Because purification imposes a lower bound on input fidelity, no path redundancy can raise the output below this threshold, which limits scaling. To address it we present the Hop-Independent Quantum Data Center (HI-QDC), an isometric, modular, scalable architecture in which purification transforms end-to-end entanglement across a module into an effective link-level resource for the inter-module topology. Our results identify the regimes in which a BCube module, under end-to-end purification, preserves both the fidelity and the yield of an elementary link. The module then hides its internal hop count and acts as an effective elementary link for a higher-level network. Thus topology supplies the path multiplicity purification requires, while purification converts it into fidelity recovery, enabling recursively scalable quantum data-center networks.
