基于里德伯原子系综中光子-光子相互作用的量子随机存取存储器实现
Quantum Random Access Memory Implementation Using Photon-Photon Interaction in Rydberg Atomic Ensemble
- S.N. Bose National Centre for Basic Sciences（S.N. 玻色基础科学国立中心）
- Sister Nivedita University（尼维迪塔姐妹大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对qRAM可扩展性瓶颈，提出基于里德伯原子系综和EIT的量子行走架构，以相位编码替代有源节点，实现对数级时间复杂度和容错硬件路径。
AI中文摘要：
量子随机存取存储器（qRAM）对于克服量子机器学习中的数据加载瓶颈至关重要；然而，当前的物理实现面临严重的可扩展性限制。传统的扇出设计需要指数级易退相干的门，而桶队列方案则需要高度易出错的有源开关。受这些限制的启发，我们提出了一种可扩展的qRAM架构，从根本上用相位编码的量子行走者取代有源节点。我们的方法将离散时间量子行走映射到腔量子电动力学框架中，利用基于电磁感应透明（EIT）的里德伯原子系综。在空芯波导内部，强的里德伯偶极-偶极相互作用和螺线管磁场产生了一个稳健的路由算子。该算子赋予精确的、偏振依赖的相移，将圆偏振探测脉冲引导至目标存储单元。我们的结果表明，在强控制场区域内操作可抑制涌现的空间衰减，确保高度扩展的存储器地址的累积传输概率。最终，这种并行化架构成功地将空间资源优化为静态门，并将时间复杂性优化为最优对数尺度$\mathcal{O}(n\log(n+m))$，同时仅需$\mathcal{O}(n+m)$个物理行走者，为先进量子计算实现建立了一条实用、容错的硬件路径。
英文摘要：
Quantum random access memory (qRAM) is crucial for overcoming data-loading bottlenecks in quantum machine learning; however, current physical implementations face severe scalability constraints. Traditional fanout designs demand exponential decoherence-prone gates, while bucket-brigade schemes require highly error-prone active switches. Motivated by these limitations, we propose a scalable qRAM architecture that fundamentally replaces active nodes with phase-encoded quantum walkers. Our methodology maps a discrete-time quantum walk onto a cavity quantum electrodynamics framework utilizing an electromagnetically induced transparency (EIT)-based Rydberg atomic ensemble. Inside hollow-core waveguides, strong Rydberg dipole-dipole interactions and a solenoidal magnetic field create a robust routing operator. This operator imparts precise, polarization-dependent phase shifts, steering circularly polarized probe pulses to target memory cells. Our results demonstrate that operating within a strong control field regime suppresses emergent spatial attenuation, ensuring cumulative transmission probabilities for highly scaled memory addresses. Ultimately, this parallelized architecture successfully optimizes spatial resources to static gates and temporal complexity to an optimal logarithmic scale of $\mathcal{O}(n\log(n+m))$ by requiring $\mathcal{O}(n+m)$ physical walkers, establishing a practical, fault-tolerant hardware pathway for advanced quantum computation implementations.
