标题： 高精度多离子光谱学与混合物种库仑晶体 显示英文标题

标题： High-accuracy multi-ion spectroscopy with mixed-species Coulomb crystals

摘要： 多离子光学钟提供了克服单离子钟低信噪比的可能性，同时仍能提供低系统不确定性。 我们展示了在直线库仑晶体中最多四个${}^{115}$In${}^+$时钟离子的同时光谱，以${}^{172}$Yb${}^+$离子进行协同冷却。 在首次时钟比较中，我们看到低于$1\times10^{-17}$的一致性，与使用单个 In${}^+$离子获得的结果一致，我们评估其系统不确定性为$2.5\times10^{-18}$。 与四个时钟离子的操作将不稳定性从$1.6\times10^{-15}/\sqrt{t/(1\;\mathrm{s})}$降低到$9.2\times10^{-16}/\sqrt{t/(1\;\mathrm{s})}$。我们推导了一个与衰减相关的状态制备死时间模型，该模型与观察到的不稳定性随时钟离子数量$N$的标度相符，并表明通过添加再泵浦激光器可以实现$1/\sqrt{N}$的标度。 显示英文摘要

摘要： Multi-ion optical clocks offer the possibility of overcoming the low signal-to-noise ratio of single-ion clocks, while still providing low systematic uncertainties. We present simultaneous spectroscopy of up to four ${}^{115}$In${}^+$ clock ions in a linear Coulomb crystal, sympathetically cooled with ${}^{172}$Yb${}^+$ ions. In first clock comparisons, we see agreement below $1\times10^{-17}$ with results obtained using a single In${}^+$ ion, for which we have evaluated the systematic uncertainty to be $2.5\times10^{-18}$. Operation with four clock ions reduces the instability from $1.6\times10^{-15}/\sqrt{t/(1\;\mathrm{s})}$ to $9.2\times10^{-16}/\sqrt{t/(1\;\mathrm{s})}$. We derive a model for decay-related dead time during state preparation, which matches the observed scaling of instability with clock ion number $N$, and indicates that $1/\sqrt{N}$ scaling can be achieved with the addition of a repump laser.