arXiv subjects

D. A. Glazov

Publications and source records attributed to D. A. Glazov.

At least 37 records · Page 2Linked to original sources

arXiv2020

Helium-like ions in magnetic field: application of the nonperturbative relativistic method for axially symmetric systems

Dirac equation for an electron bound by a nucleus in the presence of external axially symmetric field can be solved numerically by using the dual-kinetic-balance conditions imposed on the finite basis set (A-DKB method [Rozenbaum et al, Phys. Rev. A 89, 012514 (2014)]). We present the application of this method to describe helium-like ions exposed to homogeneous external magnetic field. The second-order Zeeman shift and the nuclear magnetic shielding constant are evaluated for the ground state, including the leading contribution of the interelectronic interaction. The A-DKB values are compared with the direct calculations by perturbation theory. The results for the nuclear magnetic shielding can serve for accurate determination of the nuclear magnetic moments. The quadratic contribution to the Zeeman effect can be relevant for high-precision measurements of the transition energies in helium-like ions.

physics.atom-ph↗

arXiv2020

Many-electron effects in the hyperfine splitting of lithiumlike ions

The rigorous QED evaluation of the one- and two-photon exchange corrections to the ground-state hyperfine splitting in Li-like ions is presented for the wide range of nuclear charge number $Z= 7 - 82$. The calculations are carried out in the framework of the extended Furry picture, i.e., with inclusion of the effective local screening potential in the zeroth-order approximation. The interelectronic-interaction contributions of the third and higher orders are taken into account in the framework of the Breit approximation employing the recursive perturbation theory. In comparison to the previous theoretical calculations, the accuracy of the interelectronic-interaction contributions to the ground-state hyperfine splitting in Li-like ions is substantially improved.

physics.atom-ph↗

arXiv2020

QED theory of the normal mass shift in few-electron atoms

The electron-electron interaction correction of first order in $1/Z$ to the one-electron part of the nuclear recoil effect on binding energies in atoms and ions is considered within the framework of the rigorous QED approach. The calculations to all orders in $αZ$ are performed for the $1s^2$ state in heliumlike ions and the $1s^2 2s$ and $1s^2 2p_{1/2}$ states in lithiumlike ions in the range $Z=5$--$100$. The results obtained are compared with the Breit-approximation values. The performed calculations complete a systematic treatment of the QED nuclear recoil effect up to the first order in $1/Z$. The correction obtained is combined with the previously studied two-electron part as well as the higher-order electron-correlation corrections evaluated within the Breit approximation to get the total theoretical predictions for the mass shifts.

physics.atom-ph↗

arXiv2019

Relativistic calculation of the nuclear recoil effect on the $g$ factor of the $^2P_{3/2}$ state in highly charged B-like ions

The nuclear recoil effect on the $^2 P_{3/2}$-state $g$ factor of B-like ions is calculated to first order in the electron-to-nucleus mass ratio $m/M$ in the range $Z=18$--$92$. The calculations are performed by means of the $1/Z$ perturbation theory. Within the independent-electron approximation, the one- and two-electron recoil contributions are evaluated to all orders in the parameter $αZ$ by employing a fully relativistic approach. The interelectronic-interaction correction of first order in $1/Z$ is treated within the Breit approximation. Higher orders in $1/Z$ are partially taken into account by incorporating the screening potential into the zeroth-order Hamiltonian. The most accurate to date theoretical predictions for the nuclear recoil contribution to the bound-electron $g$ factor are obtained.

physics.atom-ph↗

arXiv2019

Interelectronic-interaction contribution to the nuclear recoil effect on the $g$ factor of boronlike ions

The nuclear recoil effect on the ground-state $g$ factor of highly charged boronlike ions is considered within the relativistic framework. The interelectronic-interaction contribution is evaluated within the Breit approximation employing two independent approaches: the second-order perturbation theory and the configuration-interaction Dirac-Fock-Sturm method. The uncertainty of the nuclear recoil $g$-factor contributions is significantly reduced, especially for low- and middle-$Z$ ions.

physics.atom-ph↗

arXiv2019

QED calculations of the nuclear recoil effect on the bound-electron $g$ factor

Fully relativistic approach is applied to evaluation of the nuclear recoil effect on the bound-electron $g$ factor in hydrogenlike ions to first order in the electron-to-nucleus mass ratio $m/M$ and to all orders in $αZ$. The calculations are performed in the range $1 \leqslant Z \leqslant 20$ for the $g$ factors of $1s$, $2s$, $2p_{1/2}$, and $2p_{3/2}$ states. The $αZ$-dependence of the nontrivial QED recoil contribution as a function of $Z$ is studied.

physics.atom-ph↗

arXiv2019

QED with heavy ions: on the way from strong to supercritical fields

The current status of tests of quantum electrodynamics with heavy ions is reviewed. The theoretical predictions for the Lamb shift and the hyperfine splitting in heavy ions are compared with available experimental data. Recent achievements and future prospects in studies of the $g$ factor with highly charged ions are also reported. These studies can provide precise determination of the fundamental constants and tests of QED within and beyond the Furry picture at the strong-coupling regime. Theoretical calculations of the electron-positron pair creation probabilities in low-energy heavy-ion collisions are also considered. Special attention is paid to tests of QED in supercritical-field regime, which can be accessed in slow collisions of two bare nuclei with the total charge number larger than the critical value, $Z_{\rm crit} \approx 173$. In the supercritical field, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. It is demonstrated that this fundamental phenomenon can be observed via impact-sensitive measurements of the pair-production probabilities.

physics.atom-ph↗

arXiv2019

QED calculation of electron-electron correlation effects in heliumlike ions

Fully relativistic approach to evaluate the correlation effects in highly charged ions is presented. The interelectronic-interaction contributions of first and second orders in $1/Z$ are treated rigorously within the framework of bound-state quantum electrodynamics, whereas the calculations of the third- and higher-order contributions are based on the Dirac-Coulomb-Breit Hamiltonian. The developed approach allows one to deal with single as well as degenerate or quasi-degenerate states. We apply this approach to the calculations of the correlation contributions to the $n=1$ and $n=2$ energy levels in heliumlike ions. The obtained contributions are combined with the one-electron and screened QED corrections, nuclear recoil and nuclear polarization corrections to get the total theoretical predictions for the ionization and transition energies in high-$Z$ heliumlike ions.

physics.atom-ph↗

arXiv2019

$g$ factor of the $[(1s)^2(2s)^2 2p]~{}^2P_{3/2}$ state of middle-$Z$ boronlike ions

Theoretical \emph{g}-factor calculations for the first excited \exst state of boronlike ions in the range $Z$=10--20 are presented and compared to the previously published values. The first-order interelectronic-interaction contribution is evaluated within the rigorous QED approach in the effective screening potential. The second-order contribution is considered within the Breit approximation. The QED and nuclear recoil corrections are also taken into account.

physics.atom-ph↗

arXiv2019

$g$-factor of Boronlike Argon $^{40}\textrm{Ar}^{13+}$

We have measured the ground-state $g$-factor of boronlike argon $^{40}\textrm{Ar}^{13+}$ with a fractional uncertainty of \SI{1.4e-9}{} with a single ion in the newly developed ALPHATRAP double Penning-trap setup. The here obtained value of $g=0.663\,648\,455\,32(93)$ is in agreement with our theoretical prediction of $0.663\,648\,12(58)$. The latter is obtained accounting for quantum electrodynamics, electron correlation, and nuclear effects within the state-of-the-art theoretical methods. Our experimental result distinguishes between existing predictions that are in disagreement, and lays the foundations for an independent determination of the fine-structure constant.

physics.atom-ph↗

arXiv2019

Ground-State Energy of Uranium Diatomic Quasimolecules with One and Two Electrons

Ground-state energies of the one- and two-electron uranium dimers are calculated for internuclear distances in the range D=40--1000 fm and compared with the previous calculations. The generalization of the dual-kinetic-balance approach for axially symmetric systems is employed to solve the two-center Dirac equation without the partial-wave expansion for the potential of two nuclei. The one-electron one-loop QED contributions (self-energy and vacuum polarization) to the ground-state energy are evaluated using the monopole approximation for the two-center potential. Interelectronic interaction of the first and second order is taken into account for the two-electron quasimolecule. Within the QED approach one-photon-exchange contribution is calculated in the two-center potential, while the two-photon-exchange contribution is treated in the monopole approximation.

physics.atom-ph↗

arXiv2019

Relativistic calculations of the ground and inner-L-shell excited energy levels of berylliumlike ions

Large-scale relativistic configuration-interaction method combined with many-body perturbation theory is consistently applied to calculations of the energy levels of the ground and inner-L-shell excited states of berylliumlike ions in the range $10 \leq Z \leq 92$. The quantum electrodynamics, nuclear recoil, and frequency-dependent Breit corrections are taken into account. The obtained results are supplemented with the systematical estimation of the uncertainties.

physics.atom-ph↗

arXiv2019

$g$ Factor of Lithiumlike Silicon: New Challenge to Bound-State QED

The recently established agreement between experiment and theory for the $g$ factors of lithiumlike silicon and calcium ions manifests the most stringent test of the many-electron bound-state quantum electrodynamics (QED) effects in the presence of a magnetic field. In this Letter, we present a significant simultaneous improvement of both theoretical $g_\text{th} = 2.000\,889\,894\,4\,(34)$ and experimental $g_\text{exp} = 2.000\,889\,888\,45\,(14)$ values of the $g$ factor of lithiumlike silicon $^{28}$Si$^{11+}$. The theoretical precision now is limited by the many-electron two-loop contributions of the bound-state QED. The experimental value is accurate enough to test these contributions on a few percent level.

physics.atom-ph↗

arXiv2019

Ground-state hyperfine splitting of B-like ions in high-Z region

The hyperfine splitting of the ground state of selected B-like ions within the range of nuclear charge numbers $Z=49-83$ is investigated in detail. The rigorous QED approach together with the large-scale configuration-interaction Dirac-Fock-Sturm method are employed for the evaluation of the interelectronic-interaction contributions of first and higher orders in $1/Z$. The screened QED corrections are evaluated to all orders in $αZ$ by using an effective potential. The influence of nuclear magnetization distribution is taken into account within the single-particle nuclear model.

physics.atom-ph↗

arXiv2018

Ground-state $g$ factor of middle-$Z$ boronlike ions

Theoretical calculations of the interelectronic-interaction and QED corrections to the $g$ factor of the ground state of boronlike ions are presented. The first-order interelectronic-interaction and the self-energy corrections are evaluated within the rigorous QED approach in the effective screening potential. The second-order interelectronic interaction is considered within the Breit approximation. The nuclear recoil effect is also taken into account. The results for the ground-state $g$ factor of boronlike ions in the range $Z$=10--20 are presented and compared to the previous calculations.

physics.atom-ph↗

arXiv2018

QED calculations of the $n=2$ to $n=1$ x-ray transition energies in middle-$Z$ heliumlike ions

Ab initio QED calculations of the four x-ray transitions from the $L$ to $K$ shell in heliumlike argon, titanium, iron, copper, and krypton are performed. The binding energies for all the $n=1$ and $n=2$ states are evaluated as well. The calculation approach combines the rigorous QED treatment in the first two orders of the perturbation theory constructed within the extended Furry picture with the third- and higher-order correlation effects evaluated in the Breit approximation. The obtained results are compared with the previous evaluations and available experimental data.

physics.atom-ph↗

arXiv2018

Stringent tests of QED using highly charged ions

The present status of tests of QED with highly charged ions is reviewed. The theoretical predictions for the Lamb shift and the transition energies are compared with available experimental data. Recent achievements in studies of the hyperfine splitting and the $g$-factor isotope shift with highly charged ions are reported. Special attention is paid to tests of QED within and beyond the Furry picture at strong-coupling regime. Prospects for tests of QED at supercritical fields that can be created in low-energy heavy-ion collisions are discussed as well.

physics.atom-ph↗

arXiv2018

Relativistic nuclear recoil effect on the $g$ factor of highly charged boronlike ions

The nuclear recoil effect on the $g$ factor of the ground state of highly charged B-like ions is studied to first order in the electron-to-nucleus mass ratio $m/M$. The leading one-electron and two-electron recoil contributions are calculated nonperturbatively in the parameter $αZ$ within the rigorous QED formalism. The interelectronic-interaction correction to the nuclear recoil effect is evaluated in the Breit approximation by means of perturbation theory to the first order in $1/Z$. The higher-order interelectronic-interaction corrections are taken into account partially by performing the calculations with the effective screening potential. The results obtained represent the most accurate up-to-date treatment of the nuclear recoil effect on the $g$ factor of highly charged B-like ions in the range $Z = 20$--$92$.

physics.atom-ph↗