arXiv subjects

Yong-Bo Tang

Publications and source records attributed to Yong-Bo Tang.

15 recordsLinked to original sources

arXiv2026

$Ab$ $initio$ calculation of hyperfine-structure properties to extract nuclear magnetic octupole moments of $^{69}$Ga and $^{71}$Ga

We calculate the hyperfine-structure properties of the low-lying states in $^{69}$Ga and $^{71}$Ga using the relativistic coupled-cluster method at the singles and doubles (RCCSD) level. The properties include the first-order hyperfine constants and the second-order corrections arising from off-diagonal hyperfine interactions. Based on our theoretical results, we reanalyze the previous hyperfine-splitting measurements of the $4p_{3/2}$ state in $^{69,71}$Ga [R. T. Daly and J. H. Holloway, Phys. Rev. 96, 539 (1954)], and refine the nuclear magnetic octupole moments of these two isotopes. The refined values $\Omega(^{69}\mathrm{Ga})=0.123(9)\,\mu_N\times b $ and $\Omega(^{71}\mathrm{Ga})=0.165(15)\,\mu_N\times b $ are about 13\% and 12\% larger than the earlier results reported by Daly and Holloway. By providing the first independent \emph{ab initio} determination, the present results offer a reliable set of reference values for the magnetic octupole moments of $^{69,71}$Ga, which will benefit both future high-precision measurements and nuclear-structure calculations.

physics.atom-ph↗

arXiv2026

Hyperfine-structure constants of the $^{45}\!$Sc II ion and the nuclear quadrupole moment

In this work, we calculate the hyperfine-structure constants of the $^{45}$Sc$^{+}$ ion using a relativistic hybrid approach that combines configuration-interaction and coupled-cluster singles-and-doubles methods. Magnetic-dipole and electric-quadrupole hyperfine-structure constants are determined for the states arising from the $3d4s$, $3d^{2}$, $4s^{2}$, $4s4p$, $3d4p$, $3d5s$, $3d4d$, and $3d5p$ configurations. For most of these states, our magnetic-dipole hyperfine-structure constants agree well with available experimental data and represent a substantial improvement over previous theoretical results. By combining our calculated electric-field gradients with the measured electric-quadrupole hyperfine-structure constants for the $^{3}F_{2,3,4}$, $^{3}P_{1,2}$, and $^{1}G_{4}$ states within the $3d^{2}$ configuration, we derive a nuclear quadrupole moment $Q=-0.222(5)$ b, which is fully consistent with the value recently obtained from molecular data ( J. P. Dognon and P. Pyykk\"{o}, Phys. Chem. Chem. Phys. 27, 20453 (2025).).

physics.atom-ph↗

arXiv2026

The critical role of negative-energy states in the Land\'{e} $g$-factor of lithium-like ions

We report relativistic many-body calculations of the interelectronic-interaction correction to the Land\'{e} $g$-factor of the $2s_{1/2}$, $2p_{1/2}$, $2p_{3/2}$, and $3s_{1/2}$ states in lithium-like ions with nuclear charge $Z = 4-20$. Starting from the Dirac-Coulomb-Breit Hamiltonian, we treat positive-energy contributions using the coupled-cluster method with single and double excitations and include negative-energy contributions through third-order perturbation theory. We observe that negative-energy states give a state-dependent correction whose magnitude and sign vary with both Z and the state; for $2p_{1/2}$, the correction from the negative-energy states reaches 30\% of the total interelectronic-interaction contribution at $Z = 20$. Agreement with previous high-precision calculations is better than $0.1\%$, confirming the reliability of the present approach. This work may serve as a valuable reference for future precise calculations of $g$-factors for many-electron atomic systems.

physics.atom-ph↗

arXiv2025

Magic wavelengths and triple magic trapping conditions for $5s^2~^1\!S_0$ and $5s5p~^3\!P_{0,2}$ states of Sr atoms

The static and dynamic electric dipole polarizabilities of the $5s^2~^1\!S_0$ and $5s5p~^3\!P_{0,2}$ states of Sr atoms are calculated using the relativistic configuration interaction plus the many-body perturbation theory (RCI+MBPT) method. Magic wavelengths are determined for the transitions $5s^2~^1\!S_0\rightarrow 5s5p~^3\!P_{0}$, $5s^2~^1\!S_0\rightarrow 5s5p~^3\!P_{2}$, and $5s5p~^3\!P_0\rightarrow 5s5p~^3\!P_{2}$. A comprehensive study is conducted on the dependence of magic wavelengths on the angle between the laser polarization and the magnetic field. Furthermore, the conditions for realizing triple magic trapping at 813.4~nm for the $5s^2~^1\!S_0$, $5s5p~^3\!P_{0}$ and $5s5p~^3\!P_{2}$ states are investigated. In the case of linearly polarized light, when the angle ($\theta_p$) between the laser polarization direction and the magnetic field is $79.1(0.7)^\circ$, triple magic trapping for the $5s^2~^1\!S_0$, $5s5p~^3\!P_{0}$, and $5s5p~^3\!P_{2}~M=0$ states can be achieved. This result agrees well with the recent experimental measurement (78.49(3)$^\circ$)[Phys. Rev. Lett. 135, 143401 (2025)]. Meanwhile, triple magic trapping involving the $5s5p~^3\!P_{2}~M=2$ state can be achieved when $\theta_p= 37.4(0.3)^\circ$. The conditions for achieving triple magic trapping with circularly and arbitrarily elliptically polarized light are also presented.

physics.atom-ph↗

arXiv2025

Determination of nuclear quadrupole moments for $^{25}$Mg, $^{87}$Sr, and $^{135,137}$Ba via configuration-interaction combined with a coupled-cluster approach

Using the configuration-interaction plus coupled-cluster approach, we calculate the electric-field gradients $q$ for the low-lying states of alkaline-earth atoms, including magnesium (Mg), strontium (Sr), and barium (Ba). These low-lying states specifically include the $3s3p~^3\!P_{1,2}$ states of Mg; the $5s4d~^1\!D_{2}$ and $5s5p~^3\!P_{1,2}$ states of Sr; as well as the $6s5d~^3\!D_{1,2,3}$, $6s5d~^1\!D_{2}$, and $6s6p~^1\!P_{1}$ states of Ba. By combining the measured electric quadrupole hyperfine-structure constants of these states, we accurately determine the nuclear quadrupole moments of $^{25}$Mg, $^{87}$Sr, and $^{135,137}$Ba. These results are compared with the available data. The comparison shows that our nuclear quadrupole moment of $^{25}$Mg is in perfect agreement with the result from the mesonic X-ray experiment. However, there are approximately 10\% and 4\% differences between our results and the currently adopted values [Pyykk$\rm \ddot{o}$, Mol. Phys. 116, 1328(2018)] for the nuclear quadrupole moments of $^{87}$Sr and $^{135,137}$Ba respectively. Moreover, we also calculate the magnetic dipole hyperfine-structure constants of these states, and the calculated results exhibit good agreement with the measured data.

physics.atom-ph↗

arXiv2025

Precision calculation of hyperfine-structure constants for extracting nuclear quadrupole moment of $^{43}$Ca

There have been several reported values for the nuclear quadrupole moment of $^{43}$Ca, but significant discrepancies exist among these reported values, ranging from $-0.0408(8)$~b to $-0.065(20)$~b. In this work, we performed an accurate calculation of the electric field gradients of the $4s4p~^3\!P_{1}$, $4s4p~^3\!P_{2}$ and $4s3d~^1\!D_2$ states in the $^{43}$Ca atom using a hybrid method. This hybrid method integrates the advantages of the configuration interaction method and the coupled-cluster method, and can simultaneously account for core-core, core-valence, and valence-valence correlations. By combining our calculated results with the experimental values of the electric quadrupole hyperfine-structure constants of these three states, an accurate and reliable nuclear quadrupole moment of $^{43}$Ca was determined to be $-0.0479(6)$~b, which could be recommended as a reference for $^{43}\text{Ca}$.

physics.atom-ph↗

arXiv2024

Revisiting the hyperfine interval for the $2s2p$ $^3\!P_{J}$ state in $^9$Be

Using relativistic multiconfiguration Dirac-Hartree-Fock method, we calculate the hyperfine-structure properties of the $2s2p$ $^3\!P_{J}$ state in $^9$Be. The hyperfine-structure properties encompass first-order hyperfine-structure parameters, as well as second-order and third-order corrections arising from the hyperfine mixing of different $2s2p$ $^3\!P_{J}$ levels. Based on our theoretical results, we reanalyze the previously reported measurement of the hyperfine interval for the $2s2p$ $^3\!P$ state in $^9$Be [A. G. Blachman and A. Lurio, Phys. Rev. 153, 164(1967)], yielding updated hyperfine-structure constants. Our results show that the hyperfine-structure constant $B$ of $2s2p$ $^3\!P_{1}$ is notably sensitive to second-order correction. Conversely, accurately determining the hyperfine-structure constant $B$ of $2s2p$ $^3\!P_{2}$ necessitates consideration of the hyperfine-structure constant $C$ in the first-order hyperfine interaction equation. The updated hyperfine-structure constant $B$ of the $2s2p$ $^3\!P_{2}$ state is found to be $1.4542(67)$~MHz, which is approximately $1.7\%$ larger than the previous value of $1.427(9)$~MHz. By combining our theoretical results with the updated hyperfine-structure constant for the $2s2p$ $^3\!P_{2}$ state, we extract the electric quadrupole moment $Q$ of $^9$Be nucleus to be $0.05320(50)$~b. This value is consistent with the most recent determination using the few-body precision calculation method. Additional, we also discuss the reasons for the discrepancy between the $Q$ values obtained through few-body and previous many-body calculations.

physics.atom-ph↗

arXiv2024

Dynamic polarizabilities and triple magic trapping conditions for $5s^2~^1S_0\rightarrow 5s5p~^3P_{0,2}$ transitions of Cd atoms

The dynamic electric dipole polarizabilities of the $5s^2~^1S_0$, $5s5p~^3P_{0}$, and $5s5p~^3P_2$ states for Cd atoms are calculated using the relativistic configuration interaction plus many-body perturbation theory method. The magic wavelengths for the $5s^2~^1S_0\rightarrow 5s5p~^3P_{0}$ and $5s^2~^1S_0\rightarrow 5s5p~^3P_2$ transitions within a range of 300-500 nm are identified. The possibility of achieving triple magic trapping for the transitions $5s^2~^1S_0\rightarrow5s5p~^3P_{0}$ and $5s^2~^1S_0\rightarrow5s5p~^3P_2$ is investigated. It is found that no common magic wavelength could be identified for achieving triple magic trapping with the linearly polarized light. However, if the degree of ellipticity is between $0.358$ and $1$, the triple magic trapping can be achieved at 419.88 nm for the $5s^2 ~ ^1S_0\rightarrow 5s5p~^3P_2$ ($M_{i}=\pm2$) and $5s^2~^1S_0\rightarrow5s5p~^3P_{0}$ transitions.

physics.atom-ph↗

arXiv2024

Refined nuclear magnetic octupole moment of $^{113}$In and $^{115}$In

The refined values of the magnetic octupole moments of $^{113}$In and $^{115}$In are obtained by combining high-precision atomic calculations with corresponding hyperfine structure spectrum. We performed an \textit{ab initio }calculations of hyperfine-structure properties for the low-lying states of In atom using the single and double approximated relativistic coupled-cluster method. The hyperfine-structure properties includes first-order hyperfine-structure constants and the second-order magnetic dipole-magnetic dipole, magnetic dipole-electric quadrupole, and electric quadrupole-electric quadrupole effects caused by the off-diagonal hyperfine interaction. Based on our theoretical results, we reanalyze the previously measurements of hyperfine splitting in the 5$p_{3/2}$ state of $^{113}$In and $^{115}$In [Eck and Kusch, Phys. Rev. 106, 958 (1957)], determining corresponding hyperfine-structure constants $A$, $B$, and $C$. By combining these undated HFS constants and our theoretical results, the magnetic octupole moments of $^{113}$In and $^{115}$In nuclei are extracted to be $Ω(^{113}\rm In)=0.455(44)$~$\mathrm{μ_{N}\times b}$ , and $Ω(^{115}\rm In)=0.443(42)$~$\mathrm{μ_{N}\times b}$, respectively. The refined values of magnetic octupole moments are about smaller 21\% than the previously reported results by Eck and Kusch [Phys. Rev. 106, 958 (1957)]. Additionally, we also determine the electric quadrupole moment of $^{115}$In nuclei to be $Q(^{115}\rm In)=0.767(9)$ b by combining our theoretical results and the measured values for hyperfine-structure constants of the 5$p_{3/2}$ and 6$p_{3/2}$ states. Our results are compared with available experimental and theoretical results.

physics.atom-ph↗

arXiv2021

Relativistic coupled-cluster calculation of hyperfine-structure constants of $^{229}$Th$^{3+}$ and evaluation of the electromagnetic nuclear moments of $^{229}$Th

$^{229}$Th is a promising candidate for developing a nuclear optical clock and searching the new physics beyond the standard model. Accurate knowledge of the nuclear properties of $^{229}$Th is very important. In this work, we calculate hyperfine-structure constants for the first four states of $^{229}$Th$^{3+}$ using the relativistic coupled-cluster method based on the Gauss basis set. The no-pair Dirac-Coulomb-Breit Hamiltonian with the lowest-order quantum electrodynamics (QED) correction is the starting point, together with all linear and non-linear terms of single and double excitations are included in coupled-cluster calculation. With the measured value of the hyperfine-structure constants [Phys. Rev. Lett. 106. 223001(2011)], we get the magnetic dipole moment, $μ=0.359(9)$, and the electric quadrupole moment, $Q=2.95(7)$, of the $^{229}$Th nucleus. Our magnetic dipole moment is perfectly consistent with the recommended values, $μ=0.360(7)$, from the all-order calculation by Safronova \textit{et. al.}[Phys.Rev.A 88, 060501 (2013)], but our electric quadrupole moment is smaller than their recommended value, $Q=3.11(6)$, about 5\%. Our results show that the non-linear terms of single and double excitations, which were not included in the all-order calculation by Safronova \textit{et. al.}, are very crucial to produce a precise $Q$ value of $^{229}$Th. Additionally, we also present magnetic octupole hyperfine-structure constants and some important non-diagonal hyperfine transition matrix elements, which are required for further extracting the magnetic octupole moment $Ω$ of $^{229}$Th nucleus.

physics.atom-ph↗

arXiv2021

Relativistic coupled-cluster-theory analysis of the hyperfine interaction of Ra$^{+}$ isotopes

Hyperfine-structure constants of odd Ra$^{+}$ due to the interactions of nuclear magnetic dipole, electric quadrupole, and magnetic octupole moments with the electrons are investigated in the framework of relativistic coupled-cluster method within single- and double-excitation approximation. The calculated energies and magnetic dipole hyperfine-structure constants $A$ exhibit a good agreement with available experimental values. Combining with the experimental electric quadrupole hyperfine-structure constant, we also extracted the electric quadrupole moments $Q$ of $^{209,211,221,223}$Ra. Our $Q$($^{221}$Ra) and $Q$($^{223}$Ra) are consistent with the referenced values from a semi-empirical analysis (Z. Phys. D: At., Mol. Clusters 11, 105 (1988)), but $Q(^{211}$Ra)=$0.33(2)$ is smaller than the referenced value $0.48(4)$ by about 30\%. Furthermore, we also performed a procedure for assessing the contributions of magnetic octupole moment to the hyperfine splitting. The sensitivity of hyperfine-structure interval measurements in $^{223}$Ra$^{+}$ that can reveal the effect caused by the nuclear octupole moment are found to be on the order of kHz.

physics.atom-ph↗

arXiv2020

Magic intensity trapping of the Mg lattice clock with light shift suppressed below $10^{-19}$

Progress in atomic optical clocks with total uncertainty of $10^{-18}$ or below requires a precise estimation of multipolar and higher-order effects due to atom-field interactions. Magnesium is an attractive candidate for optical lattice clocks because it is insensitive to blackbody radiation and has a large quality factor. We employ a combined method of the Dirac-Fock plus core polarization and the relativistic configuration interaction to calculate the dynamic multipolar polarizabilities and the hyperpolarizabilities of the atomic Mg clock. The lattice light shift against variation of the laser detuning and trap depth is also investigated. We find that there exists a distinctive operational magic lattice intensity of $5.33(2)E_R$ ($E_R$ is the lattice photon recoil energy) that reduces the total light shift below $1\times 10^{-19}$ over 14\% of the trap depth variation, which will pave the way for the development of a new time-frequency standard of the Mg lattice clock.

physics.atom-ph↗

arXiv2019

Dynamic multipolar polarizabilities and hyperpolarizabilities of the Sr lattice clock

The progress in optical clock with uncertainty at a level of $10^{-18}$ requires unprecedented precision in estimating the contribution of multipolar and higher-order effects of atom-field interactions. Current theoretical and experimental results of dynamic multipolar polarizabilities and hyperpolarizabilities at the magic wavelength for the Sr clock differ substantially. We develop a combined approach of the Dirac-Fock plus core polarization (DFCP) and relativistic configuration interaction (RCI) methods to calculate dynamic multipolar polarizabilities and hyperpolarizabilities of the Sr atom. Our differential dynamic hyperpolarizability at the magic wavelength is $-2.09(43)\times10^{7}$ a.u., which is consistent with the existing theoretical and experimental results. Our differential multipolar polarizability is $2.68(94)\times 10^{-5}$ a.u., which validates independently the theoretical work of Porsev {\em et al.} [Phys. Rev. Lett. 120, 063204 (2018)], but different from recent measurement of Ushijima {\em et al.} [Phys. Rev. Lett. 121, 263202 (2018)].

physics.atom-ph↗

arXiv2019

Application of the Hylleraas-$B$-spline basis set: Nonrelativistic Bethe logarithm of helium

In this work, we report an application of Hylleraas-$B$-spline basis set to the nonrelativistic Bethe logarithm calculation of helium. The Bethe logarithm for $n\ ^1S$, $n$ up to 10, states of helium are calculated with a precision of 7-9 significant digits in two gauges, which greatly improves the accuracy of the traditional $B$-spline basis set. In addition, to deal with the numerical linear correlation problem in Bethe logarithm calculation, we developed a multiple-precision generalized symmetric eigenvalue problem solver (MGSEPS). This program may be very useful to precision calculations.

physics.atom-ph↗

arXiv2013

Dynamic polarizabilities for the low lying states of Ca+

The dynamic polarizabilities of the 4s, 3d and 4p states of Ca$^+$, are calculated using a relativistic structure model. The wavelengths at which the Stark shifts between different pairs of transitions are zero are computed. Experimental determination of the magic wavelengths can be used to estimate the ratio of the $f_{3d_{J}\to 4p_{J'}}$ and $f_{4s_{1/2} \to 4p_{J'}}$ oscillator strengths. This could prove valuable in developing better atomic structure models and in particular lead to improved values of the polarizabilities needed in the evaluation of the blackbody radiation shift of the Ca$^+$ ion.

physics.atm-clus↗