2025/02/10 by Yanmei Yu, Yu, YanMei, B. K. Sahoo +1
Physics and Astronomy · #Advanced Frequency and Time Standards #Atomic Physics (physics.atom-ph) #Atomic and Subatomic Physics Research #FOS: Physical sciences #Radioactive Decay and Measurement Techniques
paper · pdf · doi:10.48550/arxiv.2502.06225
openalex publication_date 2025/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Accurate calculations of electric dipole polarizabilities (αd), quadrupole moments (Θ), and quadrupole polarizabilities (αq) for the clock states of the singly charged calcium (Ca+) and ytterbium (Yb+) ions are presented using the general-order relativistic coupled-cluster (RCC) theory. Precise knowledge of these quantities is immensely useful for estimating uncertainties caused by major systematic effects such as the linear and quadratic Stark shifts and black-body radiation shifts in the optical Ca+ and Yb+ clocks. A finite-field approach is adopted for estimating these quantities, in which the first-order and second-order energy level shifts are analyzed by varying strengths of externally applied electric field and field-gradient. To achieve high-accuracy results in the heavier Yb+ ion, we first calculate these properties in a relatively lighter clock candidate, Ca+, which involves similar clock states. From these analyses, we learned that electron correlation effects arising from triple excitations in the RCC theory contribute significantly to the above properties, and are decisive factors in bringing the calculated values closer to the experimental results.