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V. A. Dzuba

Publications and source records attributed to V. A. Dzuba.

At least 145 records · Page 8Linked to original sources
arXiv2010

Hyperfine-mediated static polarizabilities of monovalent atoms and ions

We apply relativistic many-body methods to compute static differential polarizabilities for transitions inside the ground-state hyperfine manifolds of monovalent atoms and ions. Knowing this transition polarizability is required in a number of high-precision experiments, such as microwave atomic clocks and searches for CP-violating permanent electric dipole moments. While the traditional polarizability arises in the second-order of interaction with the externally-applied electric field, the differential polarizability involves additional contribution from the hyperfine interaction of atomic electrons with nuclear moments. We derive formulas for the scalar and tensor polarizabilities including contributions from magnetic dipole and electric quadrupole hyperfine interactions. Numerical results are presented for Al, Rb, Cs, Yb$^+$, Hg$^+$, and Fr.

physics.atom-ph↗
arXiv2010

Current trends in searches for new physics using measurements of parity violation and electric dipole moments in atoms and molecules

We review current status of the study of parity and time invariance phenomena in atoms, nuclei and molecules. We focus on three most promising areas of research: (i) parity non-conservation in a chain of isotopes, (ii) search for nuclear anapole moments, and (iii) search for permanent electric dipole moments (EDM) of atoms and molecules which are caused by either, electron EDM or nuclear $T,P$-odd moments such as nuclear EDM and nuclear Schiff moment.

physics.atom-ph↗
arXiv2010

Detection of positron-atom bound states through resonant annihilation

A method is proposed for detecting positron-atom bound states by observing enhanced positron annihilation due to electronic Feshbach resonances at electron-volt energies. The method is applicable to a range of open-shell transition metal atoms which are likely to bind the positron: Fe, Co, Ni, Tc, Ru, Rh, Sn, Sb, Ta, W, Os, Ir, and Pt. Estimates of their binding energies are provided.

physics.atom-ph↗
arXiv2010

Possibility of "magic" co-trapping of two atomic species in optical lattices

Much effort has been devoted to removing differential Stark shifts for atoms trapped in specially tailored "magic" optical lattices, but thus far work has focused on a single trapped atomic species. In this work, we extend these ideas to include two atomic species sharing the same optical lattice. We show qualitatively that, in particular, scalar J = 0 divalent atoms paired with non-scalar state atoms have the necessary characteristics to achieve such Stark shift cancellation. We then present numerical results on "magic" trapping conditions for 27Al paired with 87Sr, as well as several other divalent atoms.

physics.atom-ph↗
arXiv2010

Axio-electric effect

Using the relativistic Hartree-Fock approximation, we calculate the rates of atomic ionization by absorption of axions of the energies up to 100 keV and for an arbitrary value of the axion mass. We present numerical results for atoms used in the low radioactive background searches of dark matter (e.g. Ar, Ge and Xe), as well as the analytical formula which fits numerical calculations for the absorption cross sections and can be applied for other atoms, molecules and condensed matter systems. Using the cross-sections for the axio-electric effect, we derive the counting rates induced by solar axions and set limits on the axion coupling constants.

hep-ph↗
arXiv2010

Enhanced laboratory sensitivity to variation of the fine-structure constant using highly-charged ions

We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time-variation of the fine structure constant, alpha. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest alpha-sensitivities seen in atomic systems.

physics.atom-ph↗
arXiv2010

Relativistic many-body calculation of low-energy dielectronic resonances in Be-like carbon

We apply relativistic configuration-interaction method coupled with many-body perturbation theory (CI+MBPT) to describe low-energy dielectronic recombination. We combine the CI+MBPT approach with the complex rotation method (CRM) and compute the dielectronic recombination spectrum for Li-like carbon recombining into Be-like carbon. We demonstrate the utility and evaluate the accuracy of this newly-developed CI+MBPT+CRM approach by comparing our results with the results of the previous high-precision study of the CIII system [Mannervik et al., Phys. Rev. Lett. 81, 313 (1998)].

physics.atom-ph↗
arXiv2010

Exponential increase of energy level density in atoms: Th and Th II

We present analytical estimates and numerical calculations showing that the energy level density in open-shell atoms increases exponentially with increase of excitation energy. As an example, we use the relativistic Hartree-Fock and configuration interaction methods to calculate the density of states of Th and Th II. The result is used to estimate the effect of electrons on the nuclear transition which is considered for the use in a nuclear clock.

physics.atom-ph↗
arXiv2010

Theoretical study of the experimentally important states of dysprosium

Configuration interaction method is used to calculate transition amplitudes and other properties of the low states of dysprosium which are used in cooling and in study of the time variation of the fine structure constant and violation of fundamental symmetries. The branching ratio for the cooling state to decay to states other than ground state is found to be smaller than $10^{-4}$. The matrix element of the weak interaction between degenerate states at $E=19797.96$ cm$^{-1}$ is about 2 Hz which is consistent with the experimental limit $|H_W| = |2.3 \pm 2.9({\rm statistical}) \pm 0.7({\rm systematic})|$ Hz [A. T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Phys. Rev. A {\bf 56}, 3453 (1997)] and points to feasibility of its experimental measurement. Applications include search for physics beyond the standard model using the PNC isotopic chain approach.

physics.atom-ph↗
arXiv2010

Atomic Ionization by keV-scale Pseudoscalar Dark Matter Particles

Using the relativistic Hartree-Fock approximation, we calculate the rates of atomic ionization by absorption of pseudoscalar particles in the mass range from 10 to $\sim$ 50 keV. We present numerical results for atoms relevant for the direct dark matter searches (e.g. Ar, Ge, I and Xe), as well as the analytical formula which fits numerical calculations with few per cent accuracy and may be used for multi-electron atoms, molecules and condensed matter systems.

hep-ph↗
arXiv2009

Calculation of the (T,P)-odd Electric Dipole Moment of Thallium

Parity and time invariance violating electric dipole moment of $^{205}$Tl is calculated using the relativistic Hartree-Fock and configuration interaction methods and the many-body perturbation theory. Contributions from the interaction of the electron electric dipole moments with internal electric field and scalar-pseudoscalar electron-nucleon (T,P)-odd interaction are considered. The results are $d(^{205}{\rm Tl})=-582(20) d_e$ or $d(^{205}{\rm Tl})=-7.0(2)\times 10^{-18}C^{SP} e {\rm cm}$. Interpretation of the measurements are discussed. The results of similar calculations for $^{133}$Cs are $d(^{133}{\rm Cs})=124(4) d_e$ or $d(^{133}{\rm Cs})=0.76(2)\times 10^{-18}C^{SP} e {\rm cm}$.

physics.atom-ph↗
arXiv2009

Dynamic polarizabilities and related properties of clock states of ytterbium atom

We carry out relativistic many-body calculations of the static and dynamic dipole polarizabilities of the ground $6s^2 ^1S_0$ and the first excited $6s6p ^3P^o_0$ states of Yb. With these polarizabilities, we compute several properties of Yb relevant to optical lattice clocks operating on the $6s^2 ^1S_0 - 6s6p ^3P^o_0$ transition. We determine (i) the first four {\em magic} wavelengths of the laser field for which the frequency of the clock transition is insensitive to the laser intensity. While the first magic wavelength is known, we predict the second, the third and the forth magic wavelengths to be 551 nm, 465 nm, and 413 nm. (ii) We reevaluate the effect of black-body radiation on the frequency of the clock transition, the resulting clock shift at $T=300 \mathrm{K}$ being $-1.41(17)$ Hz. (iii) We compute long-range interatomic van der Waals coefficients (in a.u.) $C_6(6s^2 ^1S_0 +6s^2 ^1S_0) = 1909(160)$, $C_6(6s^2 ^1S_0 + 6s6p ^3P_0) =2709(338) $, and $C_6(6s6p ^3P_0 + 6s6p ^3P_0) =3886(360) $. Finally, we determine the atom-wall interaction coefficients (in a.u.), $C_3 (6s^2 ^1S_0) =3.34$ and $C_3 (6s6p ^3P_0) =3.68$. We also address and resolve a disagreement between previous calculations of the static polarizability of the ground state.

physics.atom-ph↗
arXiv2009

Calculation of the hyperfine structure of the superheavy elements Z=119 and Z=120+

The hyperfine structure constants of the lowest $s$ and $p_{1/2}$ states of superheavy elements Z=119 and Z= 120$^+$ are calculated using {\em ab initio} approach. Core polarization and dominating correlation effects are included to all orders. Breit and quantum electrodynamic effects are also considered. Similar calculations for Cs, Fr, Ba$^+$ and Ra$^+$ are used to control the accuracy. The dependence of the hyperfine structure constants on nuclear radius is discussed.

physics.atom-ph↗
arXiv2009

Calculation of P,T-odd electric dipole moments for diamagnetic atoms $^{129}$Xe, $^{171}$Yb, $^{199}$Hg, $^{211}$Rn, and $^{225}$Ra

Electric dipole moments of diamagnetic atoms of experimental interest are calculated using the relativistic Hartree-Fock and random-phase approximation methods, the many-body perturbation theory and configuration interaction technique. We consider P,T-odd interactions which give rise to atomic electric dipole moment in the second order of the perturbation theory. These include nuclear Schiff moment, P,T-odd electron-nucleon interaction and electron electric dipole moment. Interpretation of a new experimental constraint of a permanent electric dipole moment of $^{199}$Hg [W. C. Griffith {\it et al.}, Phys. Rev. Lett. {\bf 102}, 101601 (2009)] is discussed.

physics.atom-ph↗
arXiv2009

Mapping out atom-wall interaction with atomic clocks

We explore a feasibility of measuring atom-wall interaction using atomic clocks based on atoms trapped in engineered optical lattices. Optical lattice is normal to the wall. By monitoring the wall-induced clock shift at individual wells of the lattice, one would measure a dependence of the atom-wall interaction on the atom-wall separation. We rigorously evaluate the relevant clock shifts and show that the proposed scheme may uniquely probe the long-range atom-wall interaction in all three qualitatively-distinct regimes of the interaction: van der Waals (image-charge interaction), Casimir-Polder (QED vacuum fluctuations) and Lifshitz (thermal bath fluctuations). The analysis is carried out for atoms Mg, Ca, Sr, Cd, Zn, and Hg, with a particular emphasis on Sr clock.

physics.atom-ph↗
arXiv2009

The sensitivity of hyperfine structure to nuclear radius and quark mass variation

To search for the temporal variation of the fundamental constants one needs to know dependence of atomic transition frequencies on these constants. We study the dependence of the hyperfine structure of atomic $s$-levels on nuclear radius and, via radius, on quark masses. An analytical formula has been derived and tested by the numerical relativistic Hartree-Fock calculations for Rb, Cd$^+$, Cs, Yb$^+$ and Hg$^+$. The results of this work allow the use of the results of past and future atomic clock experiments and quasar spectra measurements to put constrains on time variation of the quark masses.

physics.atom-ph↗
arXiv2009

A proposed experimental method to determine $α$-sensitivity of splitting between ground and 7.6 eV isomeric states in Th-229

The 7.6 eV electromagnetic transition between the nearly degenerate ground state and first excited state in the Th-229 nucleus may be very sensitive to potential changes in the fine-structure constant, $α= e^2/\hbar c$. However, the sensitivity is not known, and nuclear calculations are currently unable to determine it. We propose measurements of the differences of atomic transition frequencies between thorium atoms (or ions) with the nucleus in the ground state and in the first excited (isomeric) state. This will enable extraction of the change in nuclear charge radius and electric quadrupole moment between the isomers, and hence the $α$-dependence of the isomeric transition frequency with reasonable accuracy.

physics.atom-ph↗