As a kind of hybrid spin system, nitrogen-vacancy (NV) centers in diamond have shown great advantages in implementing quantum registers for quantum information processing (QIP). When scaling up quantum registers to quantum networks for long-distance quantum communication and distributed quantum computation, determining how to entangle two registers in distant nodes is a basic challenge in the absence of direct interactions. In this paper, we present a scheme for entangling two distant NV centers based on the special optical absorption and emission of NV centers. In this demonstration, we transfer the entanglement information of a pair of photons to nuclear spins in NV centers and create remote NV–NV entanglement mediated by entangled photons. We then explain how to extract the entangled information from NV centers to prepare on-demand entangled photons for optical quantum information processing. The strategy of entanglement transfer between spins and photons demonstrated herein may pave the way for an NV-center-based quantum network.

中文翻译：

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基于金刚石中氮空位中心的光子吸收的预示量子纠缠转移

作为一种混合自旋系统，金刚石中的氮空位 (NV) 中心在实现量子信息处理 (QIP) 的量子寄存器方面显示出巨大优势。当将量子寄存器扩展到用于长距离量子通信和分布式量子计算的量子网络时，在没有直接交互的情况下，确定如何在远程节点中纠缠两个寄存器是一个基本挑战。在本文中，我们提出了一种基于 NV 中心的特殊光学吸收和发射的纠缠两个远距离 NV 中心的方案。在这个演示中，我们将一对光子的纠缠信息传输到 NV 中心的核自旋，并创建由纠缠光子介导的远程 NV-NV 纠缠。然后我们解释了如何从 NV 中心提取纠缠信息，以准备按需纠缠光子进行光量子信息处理。本文展示的自旋和光子之间的纠缠转移策略可能为基于 NV 中心的量子网络铺平道路。