Rare-earth ion doped crystals have proven to be solid platforms for implementing quantum memories. Their potential use for integrated photonics with large multiplexing capability and unprecedented coherence times is at the core of their attractiveness. The best performances of these ions are, however, usually obtained when subjected to a DC magnetic field, but consequences of such fields on the quantum memory protocols have only received little attention. In this paper, we focus on the effect of a DC bias magnetic field on the population manipulation of non-Kramers ions with nuclear quadrupole states, both in the spin and optical domains, by developing a simple theoretical model. We apply this model to explain experimental observations in a ${}^{151}\mathrm{Eu}:{\mathrm{Y}}_2{\mathrm{SiO}}_5$ crystal, and highlight specific consequences on the atomic frequency comb spin-wave protocol. The developed analysis should allows predicting optimal magnetic field configurations for various protocols.

中文翻译：

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弱磁场中非克拉默斯稀土离子的光学和自旋操纵，用于量子存储应用

稀土离子掺杂晶体已被证明是实现量子存储的坚实平台。它们潜在地用于具有大复用能力和前所未有的相干时间的集成光子学是其吸引力的核心。但是，这些离子的最佳性能通常是在直流磁场下获得的，但是这些场对量子存储协议的影响却鲜为人知。在本文中，我们通过建立一个简单的理论模型，重点研究了直流偏置磁场对自旋域和光学域中具有核四极态的非克拉默离子的团簇操纵的影响。我们应用此模型来解释实验观察${}^{151}\mathrm{欧盟}：{\mathrm{ÿ}}_{\mathrm{2个}}{\mathrm{二氧化硅}}_5$晶体，并强调对原子频率梳自旋波协议的特定后果。进行的分析应允许预测各种方案的最佳磁场配置。