Theoretical predictions for the Lamb shift in helium are limited by unknown quantum electrodynamic effects of the order ${\alpha }^{7}m$, where $\alpha$ is the fine-structure constant and $m$ is the electron mass. We make an important step towards the complete calculation of these effects by deriving the most challenging…

[Phys. Rev. A 101, 062516] Published Tue Jun 30, 2020

Branching fractions for decays from the $P_{3/2}$ level in ${}^{138}\mathrm{Ba}^{+}$ have been measured with a single laser-cooled ion. Decay probabilities to $S_{1/2}$, $D_{3/2}$, and $D_{5/2}$ are determined to be 0.741716(71), 0.028031(23), and 0.230253(61), respectively, which are an order-of-magnitude improvement over previous resul…

[Phys. Rev. A 101, 062515] Published Wed Jun 24, 2020

In the present work we theoretically analyze the emergence appearance of entanglement between electronic and vibrational states in a system of two coupled molecules after switching on the interaction between them. In the framework of the adiabatic approach this effect appears because the equilibrium…

[Phys. Rev. A 101, 062514] Published Tue Jun 23, 2020

QED corrections to the $g$ factor of Li-like and B-like ions in a wide range of nuclear charges are presented. Many-electron contributions as well as radiative effects on the one-loop level are calculated. Contributions resulting from the interelectronic interaction, the self-energy effect, and most o…

[Phys. Rev. A 101, 062513] Published Wed Jun 17, 2020

The electron-beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST) was employed for the measurement and detailed analysis of the $\delta \lambda ({}^{124}\mathrm{Xe},{}^{136}\mathrm{Xe})$ isotopic shifts of the Al-like $3s^{2}3p{}^{2}P_{1/2}-3s^{2}3p{}^{2}P_{3/2}$, Al-like $3s^{2}3p{}^{2}P_{1/2}-3s^{2}3d{}^{2}D_{3/2}$, Mg-like $3s^2{}^{1}S_0-3s3p{}^{1}P_1$, Mg-like $3s^2{}^{1}S_0-3s3\dots$

[Phys. Rev. A 101, 062512] Published Tue Jun 16, 2020

Extreme-ultraviolet (EUV) spectra of ${\mathrm{Sn}}^{13+}-{\mathrm{Sn}}^{15+}$ ions have been measured in an electron-beam ion trap (EBIT). A matrix inversion method is employed to unravel convoluted spectra from a mixture of charge states typically present in an EBIT. The method is benchmarked against the spectral features of r…

[Phys. Rev. A 101, 062511] Published Mon Jun 15, 2020

We are reinvestigating the hyperfine structure of sodium using a fully relativistic multiconfiguration approach. In the fully relativistic approach, the computational strategy somewhat differs from the original nonrelativistic counterpart used by P. Jönsson et al., Phys. Rev. A 53, 4021 (1996). Num…

[Phys. Rev. A 101, 062510] Published Fri Jun 05, 2020

We have measured the absolute frequency of the $2{}^{1}S_0–3{}^{1}D_2$ two-photon transitions in ${}^3\mathrm{He}$ at 1009 nm based on a cesium frequency standard through an optical frequency comb. The measured frequencies are 594 384 961.072(19) MHz for the $2{}^{1}S_{0,1/2}–3{}^{1}D_{2,5/2}$ transition and 594 384 821.209(15) MHz for the $2S_{0,\mathrm{\dots }}$

[Phys. Rev. A 101, 062507] Published Thu Jun 04, 2020

A variational theory called free-complement (FC) $s_{ij}$ theory for solving the Schrödinger equation of atoms and molecules using only one- and two-electron integrals over Slater or Gaussian functions is proposed. It is derived from the scaled Schrödinger equation [Phys Rev. Lett. 93, 030403 (2004)] by …

[Phys. Rev. A 101, 062508] Published Thu Jun 04, 2020

We report Doppler-free two-photon absorption of ${\mathrm{N}}_2\mathrm{O}$ at $\lambda =4.53\mu \mathrm{m}$, measured by cavity ring-down spectroscopy. High power was achieved by optical self-locking of a quantum cascade laser to a linear resonator of finesse $\mathcal{F}=22730$, and accurate laser detuning over a 400-MHz range was measured relative to a…

[Phys. Rev. A 101, 062509] Published Thu Jun 04, 2020

We report modulation-transfer spectroscopy (MTS) on the $6\mathit{s}6\mathit{p}{}^{3}P_0\leftrightarrow 6\mathit{s}7\mathit{s}{}^{3}S_1$ transition in neutral ytterbium (Yb) isotopes in a hollow cathode lamp. The MTS dispersive signals show an effective linewidth of 70 MHz, contributed primarily by the pressure broadening. MTS has demonstrated the capability of c…

[Phys. Rev. A 101, 062506] Published Wed Jun 03, 2020

In this paper we systematically investigate the stability of the restricted Hartree-Fock (RHF) solutions for all closed-shell atoms and ions up to xenon-like systems by means of a symmetry-adapted Thouless stability matrix. We express the RHF solution and the lowest eigenvalue of the stability matri…

[Phys. Rev. A 101, 062504] Published Tue Jun 02, 2020

We have measured the widths and energies of the $1s2s2p{}^2{P}_{1/2,3/2}\to 1s^{2}2s{}^2{S}_{1/2}$ transitions in lithiumlike sulfur and argon, as well as the energies of the forbidden $1s2s2p{}^4{P}_{5/2}\to 1s^{2}2s{}^2{S}_{1/2} M2$ transition in both elements. All measurements were performed with a double-flat-crystal spectrometer without the …

[Phys. Rev. A 101, 062505] Published Tue Jun 02, 2020

Resonant inelastic x-ray scattering (RIXS) spectra excited at the oxygen K edge of ${\mathrm{CO}}_2$ are presented and discussed. Although excitation from a gerade initial state to the intermediate $1s^{-1}{\pi }^{*}$ state breaks the inversion symmetry due to strong vibronic coupling, RIXS excited at the corresponding resona…

[Phys. Rev. A 101, 062501] Published Mon Jun 01, 2020

A state-of-the-art approach for calculating the finite-nuclear-size correction to atomic energy levels and the bound-electron $g$ factor is introduced and demonstrated for a series of highly charged hydrogenlike ions. First, self-consistent mean-field calculations based on the Skyrme-type nuclear inte…

[Phys. Rev. A 101, 062502] Published Mon Jun 01, 2020

Two recent experimental observations at the ATOMKI Institute of the Hungarian Academy of Sciences (regarding the angular emission pattern of electron-positron pairs from nuclear transitions from excited states in ${}^8\mathrm{Be}$ and ${}^4\mathrm{He}$) indicate the possible existence of a particle of a rest mass energy of rou…

[Phys. Rev. A 101, 062503] Published Mon Jun 01, 2020

The possibility of using a Raman scheme to transfer ions within a beam from the ground to a higher-lying metastable state with high-velocity selectivity is investigated. This promising scheme could find important applications in high-precision laser spectroscopy and optical high-voltage measurements, among others.

[Phys. Rev. A 101, 052512] Published Tue May 26, 2020

The electron affinity of thallium has been precisely measured using laser photodetachment threshold spectroscopy. The relative photodetachment cross section from the negative ion ${}^{205}\mathrm{Tl}^{-}$ was measured using a tunable infrared laser over the photon energy range 300–900 meV (4130–1380 nm). A pair of clo…

[Phys. Rev. A 101, 052511] Published Thu May 21, 2020

The remarkable progress in the field of laser spectroscopy induced by the invention of the frequency-comb laser has enabled many high-precision tests of fundamental theory and searches for new physics. Extending frequency-comb-based spectroscopy techniques to the vacuum and extreme ultraviolet spect…

[Phys. Rev. A 101, 052509] Published Mon May 18, 2020

We compute the Rydberg spectrum of a single ${\mathrm{Ca}}^{+}$ ion in a Paul trap by incorporating various internal and external coupling terms of the ion to the trap in the Hamiltonian. The coupling terms include spin-orbit coupling in ${\mathrm{Ca}}^{+}$, charge (electron and ionic core) coupling to the radio frequency and stat…

[Phys. Rev. A 101, 052510] Published Mon May 18, 2020

We propose a machine-learning-based approach to develop the exchange-correlation potential of time-dependent density-functional theory (TDDFT). The neural network projection from the time-varying electron densities to the corresponding correlation potentials in the time-dependent Kohn-Sham equation …

[Phys. Rev. A 101, 050501(R)] Published Fri May 15, 2020

In this paper, we report on numerical calculations of the spontaneous emission rates and Lamb shifts of a ${}^{87}\mathrm{Rb}$ atom in a Rydberg-excited state $\left(n\le 30\right)$ located close to a silica optical nanofiber. We investigate how these quantities depend on the fiber's radius, the distance of the atom to the fiber, th…

[Phys. Rev. A 101, 052508] Published Thu May 14, 2020

A QED theory of the normal mass shift in few-electron atoms is presented and applied to nuclear recoil corrections in heliumlike and lithiumlike ions. This formalism allows for highly accurate predictions for the mass shifts of the binding and transition energies.

[Phys. Rev. A 101, 052506] Published Tue May 12, 2020

We present experimental results on the sub-Doppler Rydberg spectroscopy of potassium in a hot cell and cold atoms, using two counterpropagating laser beams of 405 and 980 nm as an inverted ladder-type excitation configuration (${4S}_{1/2}\text{−}{5P}_{3/2}\text{−}n{S}_{1/2}$ and $n{D}_{3/2,5/2}$). Such an inverted ladder-type scheme is …

[Phys. Rev. A 101, 052507] Published Tue May 12, 2020

We present accurate measurements of the quadrupole S(3) and S(4) transitions of the ${\mathrm{D}}_{2}2-0$ band. Self-perturbed spectra were collected in a wide pressure range with a cavity ring-down spectrometer linked to an optical frequency comb. The results of ab initio quantum scattering calculations were incor…

[Phys. Rev. A 101, 052504] Published Mon May 11, 2020

We report measurements of the isotope shifts of two transitions ($4f^{4}6s\to {\left[25044.7\right]}_{7/2}^o$ and $4f^{4}6s\to {\left[25138.6\right]}_{7/2}^o$) in neodymium ions (${\mathrm{Nd}}^{+}$) with hundredfold improved accuracy, using laser spectroscopy of a cryogenically cooled neutral plasma. The isotope shifts were measured across a set of five spin-zero…

[Phys. Rev. A 101, 052505] Published Mon May 11, 2020

Within the framework of QED theory at finite temperature, the thermal radiative corrections to spontaneous one-photon transition rates in hydrogen atom are investigated. The radiative one-loop self-energy corrections are described in the thermal case. Closed analytical expressions are derived and th…

[Phys. Rev. A 101, 052503] Published Fri May 08, 2020

In Li et al. [Phys. Rev. A 98, 020502(R) (2018)] it was claimed that the model-potential computations of the Lamb shift on the ${}^{2}P_{1/2}-{}^{2}P_{3/2}$ fine structure in fluorinelike uranium lead to a discrepancy between theory and experiment. Later, it was reported by Volotka et al. [Phys. Rev. A 100, 010502(R)…

[Phys. Rev. A 101, 052502] Published Thu May 07, 2020

In this paper a type of thermal corrections for the helium and heliumlike atomic systems are introduced. These are the thermal one-photon exchange between the bound electrons and nucleus as well as between the bound electrons induced by the blackbody radiation (BBR). All the derivations are given wi…

[Phys. Rev. A 101, 052501] Published Mon May 04, 2020

We explore the quantum Coulomb problem for two-body bound states, in $D=3$ and $D=3-2\epsilon$ dimensions, in detail, and give an extensive list of expectation values that arise in the evaluation of QED corrections to bound-state energies. We describe the techniques used to obtain these expectation values and …

[Phys. Rev. A 101, 042511] Published Wed Apr 29, 2020

A challenge to upcoming experiments that plan to collide a particle beam with laser pulses of moderate intensity is how to correctly incorporate quantum effects into simulation frameworks. Using a uniform approach, we extend the widely used locally constant field approximation (LCFA) to derive an im…

[Phys. Rev. A 101, 042508] Published Mon Apr 27, 2020

The wavelength and rate of the $5p-5s$ transition of W xiv–W xvi ions have been calculated by the relativistic configuration interaction method with the implementation of the flexible atomic code. A reasonable collisional-radiative model has been constructed to simulate the $5p-5s$ transition spectrum o…

[Phys. Rev. A 101, 042509] Published Mon Apr 27, 2020

We measure the lifetime of the cesium $5{}^{2}D_{5/2}$ state using a time-resolved single-photon-counting method. We excite atoms in a hot vapor cell via an electric quadrupole transition at a wavelength of 685 nm and record the fluorescence of a cascade decay at a wavelength of 852 nm. We extract a lifetime …

[Phys. Rev. A 101, 042510] Published Mon Apr 27, 2020

The zero crossing of the dynamic differential scalar polarizability of the $S_{1/2}-D_{5/2}$ clock transition in ${}^{138}\mathrm{Ba}^{+}$ has been determined to be $459.1614\left(28\right)\mathrm{THz}$. Together with previously determined matrix elements and branching ratios, this tightly constrains the dynamic differential scalar polarizability …

[Phys. Rev. A 101, 042507] Published Wed Apr 22, 2020

Thallium monofluoride is a prime candidate molecule for precision measurements aimed at discovering new physics. Optical cycling on the $B\leftarrow X$ transition around 271 nm enhances this potential. Hyperfine resolved ultraviolet spectra have been reported to determine the degree of rotational level mixing i…

[Phys. Rev. A 101, 042506] Published Thu Apr 09, 2020

We measured the Kr photoelectron spectrum in the region close to the $3p$ ionization threshold. Our high-resolution measurements allowed a clear observation of spectral structures due to electron correlation effects. Analysis based on relativistic multiconfiguration calculations could explain these ob…

[Phys. Rev. A 101, 042505] Published Wed Apr 08, 2020

We have studied two-electron one-photon transitions in dielectronic recombination with H-like ions ($Z=5–54$) within ab initio QED theory. It was found that interference between dielectonic recombination with two-electron one-photon transitions and radiative recombination is prominent for light and me…

[Phys. Rev. A 101, 040501(R)] Published Tue Apr 07, 2020

We report an absolute frequency measurement of the $2s3d{}^1{D}_2$ state in neutral ${}^9\mathrm{Be}$ using two-photon spectroscopy with a resonant intermediate state. The absolute center-of-gravity energy is determined to be 64 428.40 321(55) ${\mathrm{cm}}^{-1}$, a factor of 180 more precise than the previous experimental measurement.…

[Phys. Rev. A 101, 042503] Published Mon Apr 06, 2020

We perform calculations of the $CP$-violating atomic and molecular electric dipole moments (EDMs) induced by the interaction of the nuclear Schiff moments with electrons. EDMs of atoms Eu, Dy, Gd, Ac, Th, Pa, U, Np, and Pu are of special interest since they have isotopes with strongly enhanced nuclear…

[Phys. Rev. A 101, 042504] Published Mon Apr 06, 2020

We report on spectroscopy of cold dysprosium atoms on the $1001\text{−}\mathrm{nm}$ transition and present measurements of the excited-state lifetime which is at least $87\left(7\right)\mathrm{ms}$ long. Due to the long excited-state lifetime we are able to measure the ratio of the excited-state polarizability to the ground-state polariza…

[Phys. Rev. A 101, 042502] Published Thu Apr 02, 2020

We show that existing calculations of the interaction between nuclear Schiff moments and electrons in molecules use an inaccurate operator which gives rise to significant errors. By comparing the matrix elements of the accurate and imprecise Schiff moment operators, we calculated the correction fact…

[Phys. Rev. A 101, 042501] Published Wed Apr 01, 2020

The procedure for the calculation of the self-energy-corrected wave function of the bound electron in the field of the nucleus is discussed. We present the related formulas and discuss the numerical difficulties and the methods used to overcome them. The results of the calculation are presented for …

[Phys. Rev. A 101, 032511] Published Tue Mar 24, 2020

The computation of excited electronic states with commonly employed (approximate) methods is challenging, typically yielding states of lower quality than the corresponding ground state for a higher computational cost. In this work, we present a mean-field method that extends the previously proposed …

[Phys. Rev. A 101, 032510] Published Mon Mar 23, 2020

Highly charged ion systems play an important role in simulation and diagnostics of astrophysical and fusion plasmas. Due to dominant strong Coulomb interactions from the nuclear charge, electron correlations are generally thought to be less prominent than relativistic effects and other effects in HC…

[Phys. Rev. A 101, 032508] Published Tue Mar 17, 2020

Atomic properties of S-like W are evaluated through a state-of-the-art method, namely, the multiconfiguration Dirac-Hartree-Fock method combined with the relativistic configuration-interaction approach. The level energies, wavelengths, and transition parameters involving the 88 lowest levels of ${\mathrm{W}}^{58+}$…

[Phys. Rev. A 101, 032509] Published Tue Mar 17, 2020

We study the fluctuation-induced dissipative dynamics of the quantized center-of-mass motion of a polarizable dielectric particle trapped near a surface. The particle's center of mass is treated as an open quantum system coupled to the electromagnetic field acting as its environment, with the result…

[Phys. Rev. A 101, 032507] Published Fri Mar 13, 2020

We study the Casimir pressure between two similar plates of finite thickness kept at different temperatures in the case when the dielectric permittivity of the plates depends on temperature. It is suggested to consider the dielectric permittivity at two different temperatures as the permittivities o…

[Phys. Rev. A 101, 032506] Published Wed Mar 11, 2020

We investigate the parity ($\mathcal{P}$) and time-reversal ($\mathcal{T}$) symmetry violating effects in the CdH molecule and perform the relativistic coupled-cluster calculation of the molecular parameters—$E_{\text{eff}}, W_{\text{s}}$, and $W_{\text{M}}$—related to the electric dipole moment of electron (eEDM) interaction, the scalar-pseudoscalar (S-PS…

[Phys. Rev. A 101, 032505] Published Fri Mar 06, 2020

Knowledge of the repulsive behavior of potential energy curves $V\left(R\right)$ at $R\to 0$ is necessary for understanding and modeling irradiation processes of practical interest. $V\left(R\right)$ is in principle straightforward to obtain from electronic structure calculations; however, commonly used numerical approaches for e…

[Phys. Rev. A 101, 032504] Published Thu Mar 05, 2020

We present spectroscopic measurements and detailed theoretical analysis of inner-shell $LMn$ and $LNn$ ($n\ge$ 4) dielectronic resonances in highly charged $M$-shell ions of tungsten. The x-ray emission from ${\mathrm{W}}^{49+}$ through ${\mathrm{W}}^{64+}$ was recorded at the electron-beam ion trap (EBIT) facility at the National Institute…

[Phys. Rev. A 101, 032503] Published Wed Mar 04, 2020

We implement several plasma screening potentials to calculate the level energy shifts of highly charged ions in warm dense plasmas. The Stark widths of transitions are treated with an empirical interpolation scheme combining the impact approximation and the quasicontiguous approximation. The resulti…

[Phys. Rev. A 101, 032501] Published Mon Mar 02, 2020

The exact static and time-dependent Kohn-Sham (KS) exchange-correlation potential is extremely challenging to approximate as it is a local multiplicative potential that depends on the electron density everywhere in the system. The KS approach can be generalized by allowing part of the potential to b…

[Phys. Rev. A 101, 032502] Published Mon Mar 02, 2020

Accurate three-body quantal calculations of the system composed of a proton, an antiproton, and an electron are performed in perimetric coordinates with the Lagrange-mesh method, an approximately variational calculation with the simplicity of a calculation on a grid. Quasibound states with respect t…

[Phys. Rev. A 101, 022507] Published Fri Feb 28, 2020

Quantum reflection of thermal He atoms from various surfaces (glass slide, GaAs wafer, flat, and structured Cr) at grazing conditions is studied within the elastic close-coupling formalism. Comparison with the experimental results of Zhao et al. [Phys. Rev. Lett. 105, 133203 (2010)] is quite reasona…

[Phys. Rev. A 101, 022506] Published Mon Feb 24, 2020

The QED contribution to the dipole polarizability of the ${}^4\mathrm{He}$ atom was computed, including the effect of finite nuclear mass. The computationally most challenging contribution of the second electric-field derivative of the Bethe logarithm was obtained using two different methods: the integral represe…

[Phys. Rev. A 101, 022505] Published Tue Feb 18, 2020

Beyond the metrology and computational challenges associated with molecular hydrogen, key data are expected to assess the physics of simple molecular systems, and even the new physics beyond the standard model. To assist the deciphering of Doppler-free spectra obtained at very high accuracy ($\sim {10}^{-9})$,…

[Phys. Rev. A 101, 022504] Published Thu Feb 13, 2020

We study the creation process of an electron-positron pair as a result of the collision between two incoming photons with full spatial and temporal resolution. The dynamics of the four involved particles is described by a simplified model based on a Yukawa Hamiltonian in one spatial dimension. This …

[Phys. Rev. A 101, 022503] Published Wed Feb 12, 2020

Electron affinities (EAs) of many lanthanide elements still remain unknown due to their complicated electronic structures and relatively low EA values. In the present work, we utilized the slow-velocity map-imaging method combined with an ion trap to resolve conundrums. The EA values of praseodymium…

[Phys. Rev. A 101, 022502] Published Tue Feb 11, 2020

The nonrelativistic QED (NRQED) approach is applied to the calculation of relativistic corrections to the fine and hyperfine structure of hydrogenlike atoms at orders $m{\alpha }^6$ and $m{\alpha }^6(m/M)$. Results are found to be in agreement with those of the relativistic theory. This confirms that the derived NRQED ef…

[Phys. Rev. A 101, 022501] Published Fri Feb 07, 2020

Sagnac interferometers with massive particles promise unique advantages in achieving high-precision measurements of rotation rates over their optical counterparts. Recent proposals and experiments are exploring nonballistic Sagnac interferometers where trapped atoms are transported along a closed pa…

[Phys. Rev. A 101, 012517] Published Wed Jan 29, 2020

A recently developed finite-element approach for fully numerical atomic structure calculations [S. Lehtola, Int. J. Quantum Chem. 119, e25945 (2019)] is extended to the description of atoms with spherically symmetric densities via fractionally occupied orbitals. Specialized versions of Hartree-Fock …

[Phys. Rev. A 101, 012516] Published Tue Jan 28, 2020

Short-range correlations in bosonic Helium clusters, composed of ${}^4\mathrm{He}$ atoms, are studied utilizing the generalized contact formalism. The emergence of universal $n$-body short-range correlations is formulated and demonstrated numerically via Monte Carlo simulations. The values of the $n$-particle contact…

[Phys. Rev. A 101, 010501(R)] Published Wed Jan 22, 2020

A fully relativistic approach is applied to the 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 $\alpha Z$. The calculations are performed in the range $1\le Z\le 20$ for $g$ factors of the $1s$, $2s$…

[Phys. Rev. A 101, 012513] Published Tue Jan 21, 2020

We calculate the spectra, electric dipole transition rates, and isotope shifts of the superheavy elements Ds ($Z=110$), Rg ($Z=111$), and Cn ($Z=112$) and their ions. These calculations were performed using a recently developed, efficient version of the ab intio configuration-interaction combined with per…

[Phys. Rev. A 101, 012514] Published Tue Jan 21, 2020

The nuclear recoil effect on the ground-state $g$ factor of highly charged boronlike ions is considered within the relativistic formalism. The interelectronic-interaction contribution is evaluated in the Breit approximation, employing two independent approaches: the second-order perturbation theory an…

[Phys. Rev. A 101, 012515] Published Tue Jan 21, 2020

We analyze the molecular electric dipole moments (PDMs) and static electric dipole polarizabilities of heteronuclear alkali dimers in their ground states by employing coupled-cluster theory, both in the nonrelativistic and four-component relativistic frameworks. The roles of electron correlations as…

[Phys. Rev. A 101, 012511] Published Thu Jan 16, 2020

We present a simple method for determination of absolute vibrational numbering of isolated near dissociation levels in diatomic molecules, usually observed in cold-physics experiments. The method is based on the isotope shift and works even when energies of only two levels from one isotopologue and …

[Phys. Rev. A 101, 012512] Published Thu Jan 16, 2020

The electron affinity of the lanthanum atom was recently measured by slow-electron velocity map imaging in a photodetachment experiment [Y. Lu et al., Phys. Rev. A 99, 062507 (2019)]. Several detachment threshold energies have been measured, which correspond to different energy levels of the initia…

[Phys. Rev. A 101, 016501] Published Thu Jan 16, 2020

Aiming to combine density functional theory (DFT) and wave-function theory, we study a mapping from the many-body interacting system to an effectively interacting Kohn-Sham system instead of a noninteracting Kohn-Sham system. Because a ground state of effectively interacting systems requires having …

[Phys. Rev. A 101, 012510] Published Wed Jan 15, 2020

We report a precise determination of the lifetime of the $\left(4p\right){}^2{P}_{3/2}$ state of ${}^{40}\mathrm{Ca}^{+}$, ${\tau }_{P_{3/2}}=6.639\left(42\right)\mathrm{ns}$, using a combination of measurements of the induced light shift and scattering rate on a single trapped ion. Good agreement with the result of a recent high-level theoretical calculation, 6.69(6) ns …

[Phys. Rev. A 101, 012509] Published Tue Jan 14, 2020

The quantum thermodynamical properties of (quasinormal) overdamped electromagnetic modes (eddy currents) are investigated in the context of the magnetic Casimir-Polder interaction. The role of the material response in terms of spatially local and nonlocal material models is discussed. In particular,…

[Phys. Rev. A 101, 012506] Published Mon Jan 13, 2020

The complete Auger decay of ${\mathrm{Rb}}^{+}\left(3d^{-1}\right)$ including single and double processes is investigated using the distorted wave approximation. The direct double Auger decay was calculated by separating the knock-out and shake-off mechanisms. For single Auger decay of the $3d^{-1}$ hole state, it is generally believ…

[Phys. Rev. A 101, 012507] Published Mon Jan 13, 2020

Electronic structure enhancement factors of simultaneous parity and time-reversal violation ($\mathcal{P},\mathcal{T}$ violation) caused by an electric dipole moment of the electron (eEDM) and scalar-pseudoscalar nucleon-electron current (SPNEC) interactions are reported for various metal monohydroxides, several of which…

[Phys. Rev. A 101, 012508] Published Mon Jan 13, 2020

Classical theories of radiation reaction predict that the electron motion is confined to the plane defined by the electron's instantaneous momentum and the force exerted by the external electromagnetic field. However, in the quantum radiation reaction regime, where the recoil exerted by individual q…

[Phys. Rev. A 101, 012505] Published Fri Jan 10, 2020

A recent realization of three-dimensional optical lattice clocks circumvents short-range collisional clock shifts which have been the bottle neck towards higher precision; the long-range electronic dipole-dipole interaction between the atoms becomes the primary source of clock shift due to interatom…

[Phys. Rev. A 101, 012504] Published Thu Jan 09, 2020

We theoretically characterize interactions, energetics, and chemical reaction paths in ionic two-body and three-body systems of alkali-metal and alkaline-earth-metal atoms in the context of modern experiments with cold hybrid ion-atom mixtures. Using ab initio techniques of quantum chemistry such as…

[Phys. Rev. A 101, 012501] Published Mon Jan 06, 2020

Nonlinear effects of the King plot in the isotope shifts of the 2$P$ fine-structure transitions in Be-, B-, and C-like argon ions are investigated through large-scale configuration-interaction calculations. Nonlinearities are found to be four orders of magnitude larger than previous estimates in comparable systems. This work could be important for the identification of possible nonlinearities originating from physics beyond the standard model.

[Phys. Rev. A 101, 012502] Published Mon Jan 06, 2020

We compute the ground-state electric dipole polarizability $\alpha$ of the group-13 ions using the perturbed relativistic coupled-cluster theory. To account for the relativistic effects and quantum electrodynamical corrections, we use the Dirac-Coulomb-Breit Hamiltonian with the corrections from the Uehlin…

[Phys. Rev. A 101, 012503] Published Mon Jan 06, 2020

We present measurements of the hyperfine structure splittings of $n{S}_{1/2}$ Rydberg states of ${}^{85}\mathrm{Rb}$ for $n=43$, 44, 45, and 46. From the splittings, the hyperfine coupling constant, $A_{\mathrm{HFS}}$, is determined to be 15.372(80) GHz. This result is an order-of-magnitude improvement from previous measurements. We stud…

[Phys. Rev. A 100, 062515] Published Mon Dec 30, 2019

We present an analytical and numerical analysis of the particle creation in an optomechanical cavity in parametric resonance. We treat both the electromagnetic field and the mirror as quantum degrees of freedom and study the dynamical evolution as a closed quantum system. We consider different initi…

[Phys. Rev. A 100, 062516] Published Mon Dec 30, 2019

We calculate hyperfine structure intervals $\mathrm{\Delta }{E}^{hfs}\left(2P_{1/2}\right)$ and $\mathrm{\Delta }{E}^{hfs}\left(2P_{3/2}\right)$ for $P$ states in muonic ions of lithium, beryllium, and boron. To construct the particle interaction operator in momentum space we use the tensor method of the projection operators on states with definite quantum numbers of tota…

[Phys. Rev. A 100, 062513] Published Mon Dec 23, 2019

We systematically investigate the non-Hermitian generalizations of the Landau-Zener (LZ) transition and the Landau-Zener-Stückelberg (LZS) interferometry. The LZ transition probabilities, or band populations, are calculated for a generic non-Hermitian model and their asymptotic behavior is analyzed.…

[Phys. Rev. A 100, 062514] Published Mon Dec 23, 2019

We report the first driving of the $7s{}^2{S}_{1/2}\to 6d{}^2{D}_{3/2}$ and $7s{}^2{S}_{1/2}\to 6d{}^2{D}_{5/2}$ electric quadrupole (E2) transitions in ${\mathrm{Ra}}^{+}$. We measure the frequencies of both E2 transitions and two other low-lying transitions in ${}^{226}\mathrm{Ra}^{+}$ that are important for controlling the radium ion's motional and internal states: $6d{}^2{D}_{3/\mathrm{\dots }}$

[Phys. Rev. A 100, 062512] Published Thu Dec 19, 2019

We report a theoretical calculation of the relativistic corrections to the binding energy of positronic alkali-metal atoms. The ground state for the positronic alkali-metal atom is a loosely bound state with the structure of an alkali-metal ion surrounded by a positronium cloud. The correlation betw…

[Phys. Rev. A 100, 062511] Published Tue Dec 17, 2019

We consider a bound system of charged particles moving in an external electromagnetic field, including leading relativistic corrections. The difference from the point particle with a magnetic moment comes from the presence of polarizabilities. Due to the lack of separation of the total momentum from…

[Phys. Rev. A 100, 062510] Published Mon Dec 16, 2019

It is proven that entirely spin-free wave functions can be utilized in the basic definitions of the universal functionals in density-functional theory and spin-density-functional theory. Then, for the purpose of approximating these functionals, it is shown that the knowledge of certain properties of…

[Phys. Rev. A 100, 062507] Published Fri Dec 13, 2019

We theoretically investigate Rydberg atom pair potentials of Rb atoms in front of a perfectly conducting plate. The pair potentials are perturbed by both the Casimir-Polder potential acting on a single atom and the scattering contribution to the interatomic interaction. In contrast to the pair poten…

[Phys. Rev. A 100, 062508] Published Fri Dec 13, 2019

Semiclassical electrodynamics (with quantum matter plus classical electrodynamics fields) is an appealing approach for studying light-matter interactions, especially for realistic molecular systems. However, there is no unique semiclassical scheme. On the one hand, intermolecular interactions can be…

[Phys. Rev. A 100, 062509] Published Fri Dec 13, 2019

A fully relativistic approach to evaluating 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…

[Phys. Rev. A 100, 062506] Published Tue Dec 10, 2019

The planned measurement of optical resonances in singly ionized lawrencium $(Z=103)$ requires accurate theoretical predictions to narrow the search window. We present high-precision, ab initio calculations of the electronic spectra of ${\mathrm{Lr}}^{+}$ and its lighter homologue lutetium $(Z=71)$. We have employed the…

[Phys. Rev. A 100, 062505] Published Mon Dec 09, 2019

We report a measurement of the radium ion's $7p{}^{2}P_{3/2}$ state branching fractions and improved theoretical calculations. With a single laser-cooled ${}^{226}{\mathrm{Ra}}^{+}$ ion we measure the $P_{3/2}$ branching fractions to the $7s{}^{2}S_{1/2}$ ground state $0.87678\left(20\right)$, the $6d{}^{2}D_{5/2}$ state $0.10759\left(10\right)$, and the $6d{}^{2}D_{3/2}$ state $0.01563\left(21\right)$…

[Phys. Rev. A 100, 062504] Published Fri Dec 06, 2019

Pseudopotentials are an essential ingredient in diffusion quantum Monte Carlo (DMC) calculations to increase efficiency substantially. A new generation of effective core potentials (ccECP) has been recently developed for DMC calculations. In this paper, performance of DMC using ccECP potentials on t…

[Phys. Rev. A 100, 062502] Published Tue Dec 03, 2019

As a microscopic theory to express the electromagnetic response of the system to the external fields, we present the time-dependent current-density-functional theory (td-CDFT), taking into account the effect of the energy dissipation from the system. In order to express such an effect, the non-Hermi…

[Phys. Rev. A 100, 062503] Published Tue Dec 03, 2019

To observe the dynamical Casimir effect (DCE) induced by a moving mirror is a long-standing challenge because the mirror velocity needs to approach the speed of light. Here, we present an experimentally feasible method for observing this mechanical DCE in an optomechanical system. It employs a detun…

[Phys. Rev. A 100, 062501] Published Mon Dec 02, 2019

We discuss electron diffraction from two standing waves with two different frequencies. The effects of increasing the frequency of the second laser beam and changing the laser amplitudes on the form and period of the Rabi oscillation are studied theoretically. The corresponding scattering probabilit…

[Phys. Rev. A 100, 052514] Published Wed Nov 27, 2019

We present extreme ultraviolet spectra of Ag-like ${\mathrm{W}}^{27+}$ observed with an electron beam ion trap. In the spectra, the $4f_{7/2,5/2}–5s$ electric octupole transitions are identified. Our theoretical investigation shows that the emission line intensity is strongly and specifically enhanced at the atomic numb…

[Phys. Rev. A 100, 052515] Published Wed Nov 27, 2019

Binding energies of fine structure levels of the negative ion of gallium have been determined both experimentally and theoretically, resolving long-standing discrepancies for the electron affinity of gallium. The relative photodetachment cross section from ${\mathrm{Ga}}^{-}$ ($4p^2{}^{3}P_{0,1,2}$) was measured using tunable…

[Phys. Rev. A 100, 052512] Published Tue Nov 26, 2019

Here we report on spectroscopic measurements of the aluminum monofluoride molecule (AlF; boson) that are relevant to laser cooling and trapping experiments. We measure the detailed energy-level structure of AlF in the $X{}^1{\mathrm{\Sigma }}^{+}$ electronic ground state, in the $A{}^1\mathrm{\Pi }$ state, and in the metastable $a{}^3\mathrm{\Pi }$ state. W…

[Phys. Rev. A 100, 052513] Published Tue Nov 26, 2019

We report precision measurements of the Casimir interaction at larger separation distances between the Au-coated surfaces of a sphere and a plate in ultrahigh vacuum using a much softer cantilever of the dynamic atomic-force-microscope-based setup and two-step cleaning procedure of the vacuum chambe…

[Phys. Rev. A 100, 052511] Published Mon Nov 25, 2019

The $0_0^0\tilde{A}{}^2{\mathrm{\Pi }}_{1/2}-\tilde{X}{}^2{\mathrm{\Sigma }}^{+}$, $1_1^0\tilde{A}{}^2{\mathrm{\Pi }}_{1/2}-\tilde{X}{}^2{\mathrm{\Sigma }}^{+}$, and $1_0^1\tilde{A}{}^2{\mathrm{\Pi }}_{1/2}-\tilde{X}{}^2{\mathrm{\Sigma }}^{+}$ bands of an internally cold molecular beam sample of ytterbium monohydroxide, YbOH, have been recorded at the near natural linewidth limit and analyzed to determine the fine structure parameters. Numerous lines in the $0_0^0\tilde{A}{}^2{\mathrm{\Pi }}_{1/2}-\tilde{X}{}^2{\mathrm{\Sigma }}^{+}$ band…

[Phys. Rev. A 100, 052509] Published Fri Nov 22, 2019