基于里德堡阻塞机制产生确定性窄线宽纠缠光子对的研究

窄线宽纠缠光子对是实现基于量子存储的长距离量子通信(如DLCZ方案)，以及分布式量子计算和量子网络的关键资源。然而，现有基于冷原子系综的窄线宽纠缠光子对制备方案具有不可避免的概率性缺陷，极大限制其应用效率。利用里德堡原子的阻塞效应能抑制高阶激发态的产生，实现量子纠缠态的确定性制备，从而显著提升量子中继器的连接效率和工作性能。因此，本项目拟在冷原子系综中，开展基于里德堡阻塞机制产生确定性窄线宽纠缠光子对的实验研究工作，具体研究内容为：1.在光偶极阱中俘获高密度的微小原子系综；2. 利用量子绝热捷径技术提高里德堡双光子激发过程的保真度；3. 利用相干操控手段实现从里德堡单激发态到铷原子5D5/2单激发态的转移；4. 高效而确定性地产生级联型的窄线宽纠缠光子对。本项目的实施成果将为长距离量子通信、分布式量子计算以及量子网络的发展提供支撑。

Narrowband entangled photon pairs are the key resources to realize long-distance quantum communication based on quantum memory(such as the DLCZ scheme), distributed quantum computing and quantum networks. However, the existing narrowband entangled photons preparation scheme based on cold atomic ensembles have inevitable probabilistic defects, which greatly limits their application efficiency. The blockade effect of Rydberg atom can suppress the generation of higher-order excited states and achieve the deterministic preparation of quantum entangled states, thus significantly improving the connection efficiency and working performance of quantum repeaters. Therefore, this project intends to carry out the experimental research on deterministic narrowband entangled photon pairs based on the blockade mechanism of cold Rydberg atoms. The main contents are as follows: 1. Capture the high density and tiny atomic ensemble in an optical dipole ; 2) Use the quantum adiabatic shortcut technology to enhance the fidelity of Rydberg two-photon excitation process; 3. Achieve the single excited state transfer from the Rydberg state to Rubidium 5D5 /2 state; 4. Efficiently and deterministically generate the cascade narrowband entangled photon pairs. The implementation of this project will provide support for the development of long-distance quantum communications, distributed quantum computing and quantum networks.