Precision measurement of 25Mg+-ion D1 and D2 transition frequencies

Precision measurement of Mg+ ion D1 and D2 doublet transition frequencies plays a significant part in the study of space-time variation of fundamental physical constant alpha. Here, we report a precision measurement of 25Mg+ ion D1 and D2 doublet transition frequencies using the decoherence-assisted spectroscopy method with the full use of spontaneous emission signals to improve the detection sensitivity. We obtain the D1 and D2 transition frequencies of 25Mg+ with uncertainties of 0.12 and 0.24 MHz, respectively, which are one third of that in [A. Ozawa et al., Nat. Commun. 8, 44 (2017)]. Simultaneously, we obtain the experimental and theoretical values of the 25Mg+ hyperfine structure constants in this work. The differences between the mea-sured magnetic dipole constants AP1/2 = -102.87(8 ) MHz, AP3/2 = -18.74(9 ) MHz and the theoretical values AP1/2 = -102.02(94 ) MHz, AP3/2 = -19.46(45 ) MHz are within 2o-, while the measured electric quadrupole constant BP3/2 = 24.54(45) MHz and the theoretical value of BP3/2 = 22.67(32) MHz shows a difference of more than 2o-, indicating that considerations of more physical effects in theoretical calculation, such as the possible capture of electron correlations, is required.

Automated summary

We report a precision measurement of the 25Mg+ ion D1 and D2 doublet transition frequencies using the decoherence-assisted spectroscopy method with the full use of spontaneous emission signals to improve the detection sensitivity. The obtained transition frequencies have uncertainties of 0.12 and 0.24 MHz, respectively, which are one third of a previous study. Additionally, we compare the experimental and theoretical values of the 25Mg+ hyperfine structure constants and discuss the discrepancies.