arXiv subjects

V. M. Shabaev

Publications and source records attributed to V. M. Shabaev.

At least 163 records · Page 9Linked to original sources

arXiv2006

Two-loop QED corrections in few-electron ions

Results of a calculation valid to all orders in the nuclear-strength parameter Zαare presented for the two-loop Lamb shift, notably for the two-loop self-energy correction, for the ground and first excited states of ions with the nuclear charge numbers Z=60-100. A detailed comparison of the all-order calculation with earlier investigations based on an expansion in the parameter Zαis given. The calculation removes the largest theoretical uncertainty for the 2p_j-2s transition energies in heavy Li-like ions and is important for interpretation of experimental data.

physics.atom-ph↗

arXiv2006

Quantum electrodynamics of heavy ions and atoms

The present status of quantum electrodynamics (QED) theory of heavy few-electron ions is reviewed. The theoretical results are compared with available experimental data. A special attention is focused on tests of QED at strong fields and on determination of the fundamental constants. A recent progress on calculations of the QED corrections to the parity nonconserving 6s-7s transition amplitude in neutral Cs is also discussed.

physics.atom-ph↗

arXiv2006

Screened QED corrections to the g factor of Li-like ions

The screened QED corrections to the g factor of Li-like ions are evaluated utilizing an effective potential approach. The evaluation is performed within the range of nuclear charge numbers Z=32-92. The results obtained serve for improving the theoretical predictions for the g factor of heavy Li-like ions.

physics.atom-ph↗

arXiv2006

Radiative corrections to the magnetic-dipole transition amplitude in B-like ions

The one-electron quantum-electrodynamic corrections to the magnetic-dipole transition amplitude between the fine-structure levels (1s^2 2s^2 2p) ^2P_3/2 - ^2P_1/2 in boronlike ions are calculated to all orders in (αZ). The results obtained serve for improving the theoretical accuracy of the lifetime of the (1s^2 2s^2 2p) ^2P_3/2 level in boronlike argon.

physics.atom-ph↗

arXiv2006

Electric Quadrupole Moment of a Hydrogenlike Ion in $s$ and $p_{1/2}$ States

Relativistic formulas for the electric quadrupole moment of a hydrogenlike atom, induced by the hyperfine interaction, are derived for $ns_{1/2}$ and $np_{1/2}$ states. Both the magnetic dipole and electric quadrupole hyperfine interactions are taken into account. The formulas are valid for ions with arbitrary nuclear charge and spin. The induced quadrupole moment is compared with the nuclear quadrupole moment for a wide range of hydrogenlike ions.

physics.atom-ph↗

arXiv2005

Zeeman effect of the hyperfine structure levels in hydrogenlike ions

The fully relativistic theory of the Zeeman splitting of the $1s$ hyperfine structure levels in hydrogenlike ions is considered for the magnetic field magnitude in the range from 1 to 10 T. The second-order corrections to the Breit -- Rabi formula are calculated and discussed. The results can be used for a precise determination of nuclear magnetic moments from $g$ factor experiments.

physics.class-ph↗

arXiv2005

Magnetic-dipole transition probabilities in B-like and Be-like ions

The magnetic-dipole transition probabilities between the fine-structure levels (1s^2 2s^2 2p) ^2P_1/2 - ^2P_3/2 for B-like ions and (1s^2 2s 2p) ^3P_1 - ^3P_2 for Be-like ions are calculated. The configuration-interaction method in the Dirac-Fock-Sturm basis is employed for the evaluation of the interelectronic-interaction correction with negative-continuum spectrum being taken into account. The 1/Z interelectronic-interaction contribution is derived within a rigorous QED approach employing the two-time Green function method. The one-electron QED correction is evaluated within framework of the anomalous magnetic-moment approximation. A comparison with the theoretical results of other authors and with available experimental data is presented.

physics.atom-ph↗

arXiv2005

QED Effects in Heavy Few-Electron Ions

Accurate calculations of the binding energies, the hyperfine splitting, the bound-electron g-factor, and the parity nonconservation effects in heavy few-electron ions are considered. The calculations include the relativistic, quantum electrodynamic (QED), electron-correlation, and nuclear effects. The theoretical results are compared with available experimental data. A special attention is focused on tests of QED in a strong Coulomb field.

physics.atom-ph↗

arXiv2005

Radiative and correlation effects on the parity-nonconserving transition amplitude in heavy alkaline atoms

The complete gauge-invariant set of the one-loop QED corrections to the parity-nonconserving (PNC) amplitude in cesium and francium is evaluated to all orders in $αZ$ using a local form of the Dirac-Fock potential. The calculations are performed in both length and velocity gauges for the absorbed photon and the total binding QED correction is found to be $-$0.27(3)% for Cs and $-$0.28(5)% for Fr. Moreover, a high-precision calculation of the electron-correlation and Breit-interaction effects on the 7$s-8s$ PNC amplitude in francium using a large-scale configuration-interaction Dirac-Fock method is performed. The obtained results are employed to improve the theoretical predictions for the PNC transition amplitude in Cs and Fr. Using an average value from two most accurate measurements of the vector transition polarizability, the weak charge of $^{133}$Cs is derived to amount to $ Q_W=-72.65(29)_{\rm exp}(36)_{\rm theor}$. This value deviates by $1.1σ$ from the prediction of the standard model. The values of the $7s$-$8s$ PNC amplitude in $^{223}$Fr and $^{210}$Fr are obtained to be $-$15.49(15) and $-$14.16(14), respectively, in units of i$\times 10^{-11}(-Q_W)/N$ a.u.

physics.atom-ph↗

arXiv2005

Improved all-order results for the one-loop QED correction to the hyperfine structure in light H-like atoms

A calculation of the one-loop self-energy and vacuum-polarization corrections to the hyperfine splitting of the 1s and 2s states in light H-like ions is carried out to all orders in the parameter Z α. Using the known values for the Z α-expansion coefficients, the numerical data obtained are extrapolated from Z=5 and higher to Z=0, 1, and 2, with the resulting accuracy being significantly better than in previous evaluations. Our calculation shifts the theoretical value of the normalized difference of the 1s and 2s hyperfine-structure intervals in ^3He^+ by 0.056 kHz and improves its accuracy.

physics.atom-ph↗

arXiv2005

Hyperfine splitting in heavy ions with the nuclear magnetization distribution determined from experiments on muonic atoms

The hyperfine splitting in hydrogenlike $^{209}$Bi, $^{203}$Tl, and $^{205}$Tl is calculated with the nuclear magnetization determined from experimental data on the hyperfine splitting in the corresponding muonic atoms. The single-particle and configuration-mixing nuclear models are considered. The QED corrections are taken into account for both electronic and muonic atoms. The obtained results are compared with other calculations and with experiment.

physics.atom-ph↗

arXiv2005

QED corrections to the parity-nonconserving 6s-7s amplitude in $^{133}$Cs

The complete gauge-invariant set of the one-loop QED corrections to the parity-nonconserving 6s-7s amplitude in $^{133}$Cs is evaluated to all orders in $αZ$ using a local version of the Dirac-Hartree-Fock potential. The calculations are peformed in both length and velocity gauges for the absorbed photon. The total binding QED correction is found to be -0.27(3)%, which differs from previous evaluations of this effect. The weak charge of $^{133}$Cs, derived using two most accurate values of the vector transition polarizability $β$, is $Q_W=-72.57(46)$ for $β= 26.957(51) a_{\rm B}^3$ and $Q_W=-73.09(54)$ for $β= 27.15(11)a_{\rm B}^3 $. The first value deviates by $1.1σ$ from the prediction of the Standard Model, while the second one is in perfect agreement with it.

physics.atom-ph↗

arXiv2005

Zemach and magnetic radius of the proton from the hyperfine splitting in hydrogen

The current status of the determination of corrections to the hyperfine splitting of the ground state in hydrogen is considered. Improved calculations are provided taking into account the most recent value for the proton charge radius. Comparing experimental data with predictions for the hyperfine splitting, the Zemach radius of the proton is deduced to be $1.045(16)$ fm. Employing exponential parametrizations for the electromagnetic form factors we determine the magnetic radius of the proton to be $0.778(29)$ fm. Both values are compared with the corresponding ones derived from the data obtained in electron-proton scattering experiments and the data extracted from a rescaled difference between the hyperfine splittings in hydrogen and muonium.

physics.atom-ph↗

arXiv2005

QED calculation of the n=1 and n=2 energy levels in He-like ions

We perform ab initio QED calculations of energy levels for the $n=1$ and $n=2$ states of He-like ions with the nuclear charge in the range $Z = 12$-100. The complete set of two-electron QED corrections is evaluated to all orders in the parameter $\aZ$. Uncalculated contributions to energy levels come through orders $α^3 (\aZ)^2$, $α^2 (\aZ)^7$, and higher. The calculation presented is the first treatment for excited states of He-like ions complete through order $α^2 (\aZ)^4$. A significant improvement in accuracy of theoretical predictions is achieved, especially in the high-$Z$ region.

physics.atom-ph↗

arXiv2004

Screened self-energy correction to the 2p3/2-2s transition energy in Li-like ions

We present an ab initio calculation of the screened self-energy correction for (1s)^2 2p3/2 and (1s)^2 2s states of Li-like ions with nuclear charge numbers in the range Z = 12-100. The evaluation is carried out to all orders in the nuclear-strength parameter Z α. This investigation concludes our calculations of all two-electron QED corrections for the 2p3/2-2s transition energy in Li-like ions and thus considerably improves theoretical predictions for this transition for high-Z ions.

physics.atom-ph↗

arXiv2004

Two-loop self-energy contribution to the Lamb shift in H-like ions

The two-loop self-energy correction is evaluated to all orders in Zαfor the ground-state Lamb shift of H-like ions with Z >= 10, where Z is the nuclear charge number and αis the fine structure constant. The results obtained are compared with the analytical values for the Zα-expansion coefficients. An extrapolation of the all-order numerical results to Z=1 is presented and implications of our calculation for the hydrogen Lamb shift are discussed.

hep-ph↗

arXiv2004

Two-loop self-energy correction to the ground-state Lamb shift in H-like ions

The two-loop self-energy correction is evaluated to all orders in Z alpha for the ground-state Lamb shift of H-like ions with Z >= 20, where Z is the nuclear charge number and alpha is the fine structure constant. The results obtained are compared with analytical calculations performed within the Z alpha expansion.

hep-ph↗

arXiv2004

Interelectronic-interaction effect on the transition probability in high-Z He-like ions

The interelectronic-interaction effect on the transition probabilities in high-Z He-like ions is investigated within a systematic quantum electrodynamic approach. The calculation formulas for the interelectronic-interaction corrections of first order in 1/Z are derived using the two-time Green function method. These formulas are employed for numerical evaluations of the magnetic transition probabilities in heliumlike ions. The results of the calculations are compared with experimental values and previous calculations.

physics.atom-ph↗