arXiv subjects

Tingxian Zhang

Publications and source records attributed to Tingxian Zhang.

4 recordsLinked to original sources

arXiv2023

Precision Measurement of M1 Optical Clock Transition in Ni12+

Highly charged ions (HCIs) have drawn significant interest in quantum metrology and in search for new physics. Among these, Ni12+ is considered as one of the most promising candidates for the next generation of HCI optical clocks, due to its two E1-forbidden transitions M1 and E2, which occur in the visible spectral range. In this work, we used the Shanghai-Wuhan Electron Beam Ion Trap to perform a high-precision measurement of the M1 transition wavelength. Our approach involved an improved calibration scheme for the spectra, utilizing auxiliary Ar+ lines for calibration and correction. Our final measured result of the M1 transition wavelength demonstrates a five-fold improvement in accuracy compared to our previous findings, reaching the sub-picometer level accuracy. In combination with our rigorous atomic-structure calculations to capture the electron correlations and relativistic effects, the quantum electrodynamic (QED) corrections were extracted. Moreover, comparing with an estimate of the one-electron QED contributions by using the GRASP2018 package, we found that the present experimental accuracy is high enough for testing the higher-order QED corrections for such a complex system with four electrons in the p subshell.

physics.atom-ph↗

arXiv2020

Role of hyperfine interaction in Landé $g$-factors of $^3\!P^o_0$ clock states

In the weak-magnetic-field approximation, we derived a general expression of hyperfine-induced Landé $g$-factors. By using this formula and the multi-configuration Dirac-Hartree-Fock theory, the $g$-factors were calculated for the $3s3p~^3\!P^o_0$ clock state in $^{27}$Al$^+$ and $5s5p~^3\!P^o_0$ in $^{87}$Sr. The present results, $δg^{(1)}_{\rm hfs}(^3\!P^o_0) = -1.183(6) \times 10^{-3}$ for $^{27}$Al$^+$ and $δg^{(1)}_{\rm hfs}(^3\!P^o_0) = 7.78(30) \times 10^{-5}$ for $^{87}$Sr agree with experimental values very well. Our theory is also useful to predict hyperfine-induced Landé $g$-factors for other atomic systems.

physics.atom-ph↗

arXiv2019

Reevaluation of the nuclear electric quadrupole moment for 87Sr by hyperfine structures and relativistic atomic theory

The values of nuclear electric quadrupole moment are different by about 7% for 87Sr nucleus between the recommended value [N. J. Stone, At. Data Nucl. Data Tables 111-112, 1 (2016); P. Pyykko, Mol. Phys. 116, 1328 (2018)] and earlier results [e.g. A. M. Matensson-Pendrill, J. Phys. B: At. Mol. Opt. Phys. 35, 917 (2002); K. Z. Yu et al., Phys. Rev. A 70, 012506 (2004)]. In this work, we reported a new value, Q(87Sr) = 328(4) mb, making use of our calculated electric field gradients produced by electrons at nucleus in combination with experimental values for hyperfine structures of the 5s5p 3P1,2 states of the neutral Sr atom. In the framework of the multi-configuration Dirac-Hartree-Fock theory, the electron correlations were taken into account systematically so as to control the uncertainties of the electric field gradient at about 1% level. The present result is different from the recommended value, but in excellent agreement with those by Matensson-Pendrill and Yu et al.. We would recommend the present Q value as a reference for 87Sr.

physics.atom-ph↗

arXiv2017

Theoretical study on the hyperfine interaction constants and the isotope shift factors for the $3s^2~^1 S_{ 0} ~-~ 3s3p~^{3,1}P^o_1$ transitions in Al$^+$

We calculated the magnetic dipole and the electric quadrupole hyperfine interaction constants of 3s3p $^{3,1}P^o_1$ states and the isotope shift, including mass and field shift, factors for transitions from these two states to the ground state 3s$^2~^1S_0$ in Al$^+$ ions using the multiconfiguration Dirac-Hartree-Fock method. The effects of the electron correlations and the Breit interaction on these physical quantities were investigated in detail based on the active space approach. It is found that the CC and the higher-order correlations are considerable for evaluating the uncertainties of the atomic parameters concerned. The uncertainties of the hyperfine interaction constants in this work are less than 1.5\%. Although the isotope shift factors are highly sensitive to the electron correlations, reasonable uncertainties were obtained by exploring the effects of the electron correlations. Moreover, we found that the relativistic nuclear recoil corrections to the mass shift factors are very small and insensitive to the electron correlations for Al$^{+}$. These atomic parameters present in this work are valuable for extracting the nuclear electric quadrupole moments and the mean-square charge radii of Al isotopes.

physics.atom-ph↗