Sensitivity to New Physics of Isotope Shift Studies using the Coronal Lines of Highly Charged Calcium Ions

The $g$ factor of bound electrons as a test for physics beyond the Standard Model

The use of high-precision measurements of the $g$ factor of few-electron ions and its isotope shifts is put forward as a probe for physics beyond the Standard Model. The contribution of a hypothetical fifth fundamental force to the $g$ factor is calculated for the ground state of H-like, Li-like and B-like ions, and employed to derive bounds on the parameters of that force. The weighted difference and especially the isotope shift of $g$ factors are used in order to increase the experimental sensitivity to the new physics contribution. It is found that, combining measurements from four differen…

全面纳入King图中的高阶Ca⁺同位素位移可使e⁻-n耦合极限提升一个数量级

Comprehensive Inclusion of Higher-order Ca$^+$ Isotope Shifts in the King's Plot Yields an Order Improvement on the $e^-$-$n$ Coupling Limit

本研究通过纳入Ca⁺同位素位移的高阶非线性效应，结合两种相对论耦合簇方法计算相关参数，将电子-中子耦合的约束极限提升一个数量级，明确了高阶效应和电子关联的作用。

Unexpectedly large difference of the electron density at the nucleus in the 4p $^2$P$_{1/2,3/2}$ fine-structure doublet of Ca$^+$

We measured the isotope shift in the $^2$S$_{1/2}$-$^2$P$_{3/2}$ (D2) transition in singly-ionized calcium ions using photon recoil spectroscopy. The high accuracy of the technique enables us to resolve the difference between the isotope shifts of this transition to the previously measured isotopic shifts of the $^2$S$_{1/2}$-$^2$P$_{1/2}$ (D1) line. This so-called splitting isotope shift is extracted and exhibits a clear signature of field shift contributions. From the data we were able to extract the small difference of the field shift coefficient and mass shifts between the two transitions …

Catching, trapping and in-situ-identification of thorium ions inside Coulomb crystals of $^{40}$Ca$^+$ ions

Thorium ions exhibit unique nuclear properties with high relevance for testing symmetries of nature, and Paul traps feature an ideal experimental platform for performing high precision quantum logic spectroscopy. Loading of stable or long-lived isotopes is well-established and relies on ionization from an atomic beam. A different approach allows trapping short-lived isotopes available as alpha-decay daughters, which recoil from a thin sample of the precursor nuclide. A prominent example is the short-lived $^{229\text{m}}$Th, populated in a decay of long-lived $^{233}$U. Here, ions are provided…

Probing "long-range" neutrino-mediated forces with atomic and nuclear spectroscopy

The exchange of a pair of low-mass neutrinos between electrons, protons and neutrons produces a "long-range" $1/r^5$ potential, which can be sought for in phenomena originating on the atomic and sub-atomic length scales. We calculate the effects of neutrino-pair exchange on transition and binding energies in atoms and nuclei. In the case of atomic s-wave states, there is a large enhancement of the induced energy shifts due to the lack of a centrifugal barrier and the highly singular nature of the neutrino-mediated potential. We derive limits on neutrino-mediated forces from measurements of the…

研究三激发在高精度确定碱土金属单电荷离子钟态电偶极极化率和四极矩中的作用

Investigating Roles of Triple Excitations for High-precision Determination of Clock Properties of Alkaline Earth Metal Singly Charged Ions

本文利用RCC理论研究三激发对高精度确定碱土金属单电荷离子钟态电偶极极化率和四极矩的作用，发现其结果与文献值存在显著差异。