Two-time Green's function method in quantum electrodynamics of high-/Z few-electron atoms

Electronic states of highly charged ions show magnified fine-structure, Lamb shift, and hyperfine effects making them sensitive probes of bound-state quantum electrodynamics and nuclear physics. Being also impervious to external perturbations renders them ideal candidates for precision spectroscopy and accurate clocks that could test physics beyond the standard model. This review discusses how a variety of ion species and transitions may optimally be used to target such new applications, and presents routes to handle them in the laboratory.

Highly charged ions: Optical clocks and applications in fundamental physics

This paper reviews some of the fundamental properties of highly charged ions, the methods of producing them (with particular emphasis on table-top devices), and their use as a tool for both basic science and applied technology. Topics discussed include: charge dependence and scaling laws along isoelectronic or isonuclear sequences (for wavefunction size or Bohr radius, ionization energy, dipole transition energy, relativistic fine structure, hyperfine structure, Zeeman effect, Stark effect, line intensities, linewidths, strength of parity violation, etc), changes in angular momentum coupling schemes, selection rules, interactions with surfaces, electron-impact ionization, the electron beam ion trap (EBIT), ion accelerators, atomic reference data, cosmic chronometers, laboratory x-ray astrophysics, vacuum polarization, solar flares, ion implantation, ion lithography, ion microprobes (SIMS and x-ray microscope), nuclear fusion diagnostics, nanotechnology, quantum computing, cancer therapy and biotechnology.

https://iopscience.iop.org/article/10.1088/0953-4075/34/19/201/pdf

Highly charged ions

The gj factor of a bound electron and the hyperfine structure splitting in hydrogenlike ions

Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

Beta decay of highly charged ions

The ground-state hyperfine splitting values of high-Z hydrogenlike ions are calculated. The relativistic, nuclear, and QED corrections are taken into account. The nuclear magnetization distribution correction (the Bohr-Weisskopf effect) is evaluated within the single-particle model with the g{sub S} factor chosen to yield the observed nuclear moment. An additional contribution caused by the nuclear-spin-orbit interaction is included in the calculation of the Bohr-Weisskopf effect. It is found that the theoretical value of the wavelength of the transition between the hyperfine-splitting components in {sup 165}Ho{sup 66+} is in good agreement with experiment. {copyright} {ital 1997} {ital The American Physical Society}

Ground-state hyperfine splitting of high-Z hydrogenlike ions

The ground-state hyperfine splitting values and the transition probabilities between the hyperfine structure components of high-$Z$ lithiumlike ions are calculated in the range $Z=49$--83. The relativistic, nuclear, QED, and interelectronic interaction corrections are taken into account. It is found that the Bohr-Weisskopf effect can be eliminated in a combination of the hyperfine splitting values of the hydrogenlike and lithiumlike ions of an isotope. This gives a possibility for testing the QED effects in a combination of the strong electric and magnetic fields of the heavy nucleus. Using the experimental result for the $1s$ hyperfine splitting in ${}^{209}{\mathrm{Bi}}^{82+}$, the $2s$ hyperfine splitting in ${}^{209}{\mathrm{Bi}}^{80+}$ is calculated to be $\ensuremath{\Delta}E=0.7976(2)$ eV.

https://arxiv.org/pdf/physics/9707006.pdf

Transition energy and lifetime for the ground-state hyperfine splitting of high- Z lithiumlike ions

Hyperfine splittings of hydrogenlike ions and the dynamic-correlation model for one-hole nuclei

Erratum: Transition energy and lifetime for the ground-state hyperfine splitting of high-Z lithiumlike ions [Phys. Rev. A 57, 149 (1998)]

The matter and the charge distributions of the 6 He and 5,6,7,9 Li isotopes are investigated within the dynamiccorrelation model ~DCM! which describes the ground states of light nuclei in terms of microscopic correlated clusters: the valence particles and the intrinsic vacuum states. The amplitudes of these mixed-mode wave functions are calculated in the framework of nonperturbative solutions of the equation of motion method ~EOMM!. The matter and charge mean square radii are in good agreement with experimental results. The calculated matter distribution of the 6 He nucleus is characterized by a halo structure less pronounced than that calculated by the three cluster models. The charge distribution of 6 Li reproduces well the electron scattering data. Good agreement with experimental data has been also achieved for the proton scattering cross sections of p- 6 He at an energy of 0.7 GeV/nucleon. PACS number~s!: 21.10.Gv, 21.10.Ft, 21.60.2n, 27.20.1n The shape of the matter and of the charge distributions, as well as the matter and the charge radii of light nuclei can be extracted unambiguously from the analysis of proton scattering @1#, electron scattering @2#, and from isotope shift @3# measurements. The distributions of 6 He and 6 Li reveal a new type of nuclear structure, where the core is surrounded by nuclear matter which contribute to the formation of an extended, far reaching one or two neutron halo @4#. Theoretical calculations of the 2n-halo structures have been, up to now, performed in the Borromean three rings approximation @4# firstly introduced to investigate the halo structure of 11 Li. Within this assumption the valence neutrons interact via the neutron-neutron interaction, without exciting the closed-shell reference nucleus which remains in its ground state. The interaction between the valence- and the core-particle has been neglected under the assumption that the valence neutrons are weakly bound. In the three-cluster model of Ref. @4# the a-particle core is simply represented by a $0s% 4 harmonic oscillator state. Only recently the excitations of the a particle @5# have been introduced in the calculations of the halo structure within a macroscopic core breakup mechanism @6#. This paper provides a new microscopic description of the matter and charge distributions of 6 He and 5,6,7,9 Li isotopes based on the DCM which was first introduced in Refs. @7,8# to investigate the electromagnetic structure of heavy nuclei. The model describes the ground and excited states of nuclei in terms of valence particles interacting with the excited structure of the core. These additional terms, not considered by the up to now published theories, are important in the analysis of the halo structure of exotic nuclei because the deformation of the nuclear core is reshaping, at high momenta, the tail of the nuclear distributions. The theoretical formalism discussed in this paper is used to describe simultaneously either nuclei characterized by an odd or by an even number of valence particles. For odd nuclei we perform calculations according to Refs. @7,8#, while to describe nuclei with an even number of valence particles we modify the dynamic model via introducing the boson dynamic correlation model ~BDCM!. Within the DCM and the BDCM, the charge and the matter distributions of 6 He and 5,6,7,9 Li ground states are calculated defining mixed-mode states as non-perturbative solutions of the EOMM. The following mixed-mode states have been discussed: the $p%1$2p 21h% for 5 Li, the $h%1$2h21p% for 7 Li, the $2p%1$3p 21h% for 6 He and 6 Li, and the $2p21h%1$3p22h% for 9 Li. The higher order components of the ground state wave functions have an unperturbed energy much larger than the corresponding $n% body matrix elements and contribute poorly to the active subspaces and are not included explicitly in the model space. These components however, properly linearized, define the mean field potential of the mixed-mode states. The mixed-mode states obtained within this approximation form the base-vectors in which the ground state energies, the matter and charge radii, and the matter and charge distributions are calculated. The charge radii of the radioactive lithium isotopes preliminarily calculated in Ref. @9#, have not yet been measured. They will be provided by isotope shift measurements on the 2 2 S-3 2 S transitions which is theoretically supported by the analysis performed in Ref. @10#. These experiments are going on presently at GSI @11#. With the calculated distributions it is possible then to analyze ~matter distributions! the elastic proton scattering in the inverse scattering geometry done at GSI and ~charge distributions! the electron scattering experiments. In recent experi

M. Tomaselli

Papers

Ground-state hyperfine splitting of high-Z hydrogenlike ions

Transition energy and lifetime for the ground-state hyperfine splitting of high- Z lithiumlike ions

Hyperfine splittings of hydrogenlike ions and the dynamic-correlation model for one-hole nuclei

Erratum: Transition energy and lifetime for the ground-state hyperfine splitting of high-Z lithiumlike ions [Phys. Rev. A 57, 149 (1998)]

Matter and charge distributions of 6 He and 5,6,7,9 Li within the dynamic-correlation model