发表机构
S.N. Bose National Centre for Basic Sciences; Sister Nivedita University（S.N. Bose 基础科学国家中心; Sister Nivedita 大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出基于里德伯阻塞EIT系统的量子随机行走qRAM架构，利用偶极相互作用实现高保真相位控制，复杂度为O(n)，无需低温。
AI 中文摘要
我们提出了一种新颖的理论架构，用于在利用多能级电磁感应透明（EIT）的里德伯阻塞原子系综中，基于量子随机行走实现量子随机存取存储器（qRAM）。与以往依赖固态或离子阱系统中几何相位门的方法不同，我们的方案利用里德伯原子之间强且相干的偶极-偶极相互作用，在无需低温条件下实现对光子量子比特的高保真相位控制。通过在多个λ型EIT系统中通过交叉相位调制产生条件相移，我们实现了高效qRAM所需的受控幺正操作。在所提出的架构中，利用塞曼分裂在腔中构建一组平行的λ系统，其中基态的成对磁子能级通过圆偏振激光脉冲耦合到高度激发的里德伯态。这些里德伯激发的EIT系统作为基本相位门，构成二叉树节点，实现量子随机行走。地址和数据量子比特被编码到不同的探针场中，并相干地映射到亚稳态原子态，它们在EIT介质内的相互作用产生条件相位，用于状态选择性路由。该系统使用$n+m$层冷碱金属原子形成$n$级里德伯节点二叉树，连接到$2^n$个腔捕获存储原子，由$n+m$个激光脉冲作为量子行走器和地址单元操作。我们的方案提供了一条可扩展、将操作复杂度降低至$\mathcal{O}(n)$且高度相干的路径，用于光子qRAM，利用集体里德伯相互作用在原子系综中实现可编程的并行纠缠操作。
英文摘要
We propose a novel theoretical architecture for implementing a quantum random access memory (qRAM) based on quantum random walks in a Rydberg blockaded atomic ensemble utilizing multilevel Electromagnetically Induced Transparency (EIT). Unlike previous approaches that rely on geometric phase gates in solid-state or trapped ion systems, our scheme harnesses the strong, coherent dipole dipole interactions between Rydberg atoms to achieve high-fidelity phase control of photonic qubits without the need for cryogenic temperatures. By generating conditional phase shifts through cross-phase modulation in multiple lambda-type EIT systems, we realize the controlled unitary operations requisite for an efficient qRAM. In the proposed architecture, Zeeman splitting is used to engineer a set of parallel lambda systems in a cavity, where pairs of magnetic sublevels of the ground state are coupled to highly excited Rydberg states via circularly polarized laser pulses. These Rydberg excited EIT systems serve as the elementary phase gates that form the nodes of a binary tree enabling quantum random walking. Address and data qubits are encoded into distinct probe fields and coherently mapped into the metastable atomic states, where their interactions within the EIT medium generate conditional phases required for state-selective routing. The system uses $n+m$ layers of cold alkali atoms to form an $n$-level binary tree of Rydberg nodes connected to $2^n$ cavity-trapped memory atoms, operated by $n+m$ laser pulses acting as quantum walkers and address units. Our scheme offers a scalable, reducing operational complexity to $\mathcal{O}(n)$ and highly coherent pathway toward photonic qRAM, exploiting collective Rydberg interactions to realize programmable, parallel entangling operations in an atomic ensemble.
CommentsBibTeX, Version 0.99d (MiKTeX 25.4), 13 pages and 10 figures, submitted to Journal of Physics B
