J. S. M. Ginges

Violations of fundamental symmetries in atoms and tests of unification theories of elementary particles

High-precision measurements of violations of fundamental symmetries in atoms are a very effective means of testing the standard model of elementary particles and searching for new physics beyond it. Such studies complement measurements at high energies. We review the recent progress in atomic parity nonconservation and atomic electric dipole moments (time reversal symmetry violation), with a particular focus on the atomic theory required to interpret the measurements.

High-precision calculation of parity nonconservation in cesium and test of the standard model

We have calculated the 6s-7s parity nonconserving (PNC) E1 transition amplitude, E_{PNC}, in cesium. We have used an improved all-order technique in the calculation of the correlations and have included all significant contributionsto E_{PNC}. Our final value E_{PNC} = 0.904 (1 +/- 0.5 %) \times 10^{-11}iea_{B}(-Q_{W}/N) has half the uncertainty claimed in old calculations used for the interpretation of Cs PNC experiments. The resulting nuclear weak chargeQ_{W} for Cs deviates by about 2 standard deviations from the value predicted by the standard model.

Calculation of parity and time invariance violation in the radium atom.

Parity (P) and time (T) invariance violating effects in the Ra atom are strongly enhanced due to close states of opposite parity, the large nuclear charge Z and the collective nature of [Formula Presented]-odd nuclear moments. We have performed calculations of the atomic electric dipole moments (EDM) produced by the electron EDM and the nuclear magnetic quadrupole and Schiff moments. We have also calculated the effects of parity nonconservation produced by the nuclear anapole moment and the weak charge. Our results show that as a rule the values of these effects are much larger than those considered so far in other atoms (enhancement is up to [Formula Presented] times).

Calculations of parity-nonconserving s − d amplitudes in Cs, Fr, Ba + , and Ra +

We have performed ab initio mixed-states and sum-over-states calculations of parity nonconserving (PNC) electric dipole (E1) transition amplitudes between s-d electron states of Cs, Fr, Ba II, and Ra II. For the lower states of these atoms we have also calculated energies, E1 transition amplitudes, and lifetimes. We have shown that PNC E1 transition amplitudes between s-d states can be calculated to high accuracy. Contrary to the Cs 6s-7s transition, in these transitions there are no strong cancelations between different terms in the sum-over-states approach. In fact, there is one dominating term which deviates from the sum by less than 20%. This term corresponds to an s-p_{1/2} weak matrix element, which can be calculated to better than 1%, and a p_{1/2}-d_{3/2} E1 transition amplitude, which can be measured. Also, the s-d amplitudes are about four times larger than the corresponding s-s transitions. We have shown that by using a hybrid mixed-states/sum-over-states approach the accuracy of the calculations of PNC s-d amplitudes could compete with that of Cs 6s-7s if p_{1/2}-d_{3/2} E1 amplitudes are measured to high accuracy.

Nuclear Schiff moment and time-invariance violation in atoms

A consistent theory of the nuclear Schiff moment and the electric dipole moment (EDM) it induces was established. The resulting theory properly takes into consideration the relativistic character of the electron wave functions inside the nucleus.

Calculations of energy levels and lifetimes of low-lying states of barium and radium

We use the configuration-interaction method and many-body perturbation theory to perform accurate calculations of energy levels, transition amplitudes, and lifetimes of low-lying states of barium and radium. Calculations for radium are needed for the planning of measurements of parity- and time-invariance-violating effects which are strongly enhanced in this atom. Calculations for barium are used to control the accuracy of the calculations.

Calculation of the spectrum of the superheavy element Z = 120

School of Physics, University of New South Wales, Sydney NSW 2052, Australia(Dated: September 5, 2008)High-precision calculations of the energy levels of the superheavy element Z = 120 are presented.The relativistic Hartree-Fock and configuration interaction techniques are employed. The correla-tions between core and valence electrons are treated by means of the correlation potential methodand many-body perturbation theory. Similar calculations for barium and radium are used to gaugethe accuracy of the calculations and to improve the ab initio results.

Calculations of the spectra of superheavy elements Z = 119 and Z = 120 +

High-precision calculations of the energy levels of the superheavy elements Z=119 and Z= 120+ are presented. Dominating correlation corrections beyond the relativistic Hartree-Fock method are included to all orders in the Coulomb interaction using the Feynman diagram technique and the correlation potential method. The Breit interaction and quantum electrodynamics radiative corrections are considered. Also, the volume isotope shift is determined. A similar treatment for Cs, Fr, Ba+, and Ra+ is used to gauge the accuracy of the calculations and to refine the ab initio results.

Spectra of barium, radium, and element 120: application of the combined correlation-potential, singles-doubles, and configuration-interaction ab initio methods

We apply a version of the recently developed approach combining the correlation-potential, linearized singles-doubles coupled-cluster, and configuration-interaction methods to the spectra of the heavy alkaline earths barium, radium, and element 120. Quantum electrodynamics radiative corrections are included. We have found excellent agreement between ab initio theory and experiment for the spectra of barium and radium, and we make accurate predictions for missing and unreliable data for all three atoms.

Atomic electric dipole moments of He and Yb induced by nuclear Schiff moments

We have calculated the atomic electric dipole moments (EDMs) d of {sup 3}He and {sup 171}Yb induced by their respective nuclear Schiff moments S. Our results are d({sup 3}He)=8.3x10{sup -5} and d({sup 171}Yb)=-1.9 in units of 10{sup -17}(S/e fm{sup 3}) e cm. By considering the nuclear Schiff moments induced by the parity- and time-reversal violating nucleon-nucleon interaction, we find d({sup 171}Yb){approx}0.6d({sup 199}Hg). For {sup 3}He the nuclear EDM coupled with the hyperfine interaction gives a larger atomic EDM than the Schiff moment. The result for {sup 3}He is required for a neutron EDM experiment that is under development, where {sup 3}He is used as a comagnetometer. We find that the EDM for {sup 3}He is orders of magnitude smaller than the neutron EDM. The result for {sup 171}Yb is needed for the planning and interpretation of experiments that have been proposed to measure the EDM of this atom.