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A systematic investigation of the nuclear polarization effects in one- and few-electron heavy ions is presented. The nuclear polarization corrections in the zeroth and first orders in 1 /Z are evaluated to the binding energies, the hyperfine splitting, and the bound-electron g factor. It is shown that the nuclear polarization contributions can be substantially canceled simultaneously with the rigid nuclear corrections. This allows for new prospects for probing the QED effects in a strong electromagnetic field and the determination of fundamental constants. [ABSTRACT FROM AUTHOR]

Abstract: The inelastic high-energy photon scattering from helium-like ions in the metastable and states, which results in ionization accompanied by simultaneous excitation of the residual ion, is considered. The description is performed within the framework of nonrelativistic perturbation theory. The cross sections of the process for transitions into the ns states are deduced in the analytical form. The contributions of excitations into the nl states characterized by the angular momentum are negligibly small. A comparison of our results with those of approximate calculations is given. [Copyright &y& Elsevier]

Wavefunction-splitting or mask method, widely used in the non-relativistic calculations of the photoelectron angular distributions, is extended to the relativistic domain within the dipole approximation. Since the closed-form expressions for the relativistic Volkov states are not available within the dipole approximation, we build such states numerically solving a single second-order differential equation. We calculate the photoelectron energy spectra and angular distributions for highly charged ions under different ionization regimes with both the direct and the relativistic mask methods. We show that the relativistic mask method works very well and reproduces the electron energy and angular distributions calculated by the direct method in the energy range where both methods can be used. On the other hand, the relativistic mask method can be applied for longer laser pulses and/or higher photoelectron energies where the direct method may have difficulties. [ABSTRACT FROM AUTHOR]

While water lifting plays a recognized role in the global atmospheric power budget, estimates for this role in tropical cyclones vary from no effect to a major reduction in storm intensity. To better assess this impact, here we consider the work output of an infinitely narrow thermodynamic cycle with two streamlines connecting the top of the boundary layer in the vicinity of maximum wind (without assuming gradient-wind balance) to an arbitrary level in the inviscid free troposphere. The reduction of a storm's maximum wind speed due to water lifting is found to decline with increasing efficiency of the cycle and is about 5% for maximum observed Carnot efficiencies. In the steady-state cycle, there is an extra heat input associated with the warming of precipitating water. The corresponding positive extra work is of an opposite sign and several times smaller than that due to water lifting. We also estimate the gain of kinetic energy in the outflow region. Contrary to previous assessments, this term is found to be large when the outflow radius is small (comparable to the radius of maximum wind). Using our framework, we show that Emanuel's maximum potential intensity (E-PI) corresponds to a cycle where total work equals work performed at the top of the boundary layer (net work in the free troposphere is zero). This constrains a dependence between the outflow temperature and heat input at the point of maximum wind, but does not constrain the radial pressure gradient. We outline the implications of the established patterns for assessing real storms. [ABSTRACT FROM AUTHOR]

Recent progress in quantum electrodynamics (QED) calculations of highly charged ions is reviewed. The theoretical predictions for the binding energies, the hyperfine splittings, and the g factors are presented and compared with available experimental data. Special attention is paid to tests of bound-state QED at strong field regime. Future prospects for tests of QED at the strongest electric and magnetic fields as well as for determination of the fine structure constant and the nuclear magnetic moments with heavy ions are discussed. [ABSTRACT FROM AUTHOR]

Abstract: A review of the current status of the theoretical study of spectral line profile for systems with few electrons is given in this paper. The hydrogen atom and highly charged ions are presented in this work. In particular, the line profiles for cascade processes, the asymmetry of the line profile beyond the resonance approximation and the overlap of the resonances are investigated. The line profile approach is introduced for the investigation of the energy levels and the transition probabilities for bound electrons within the framework of quantum electrodynamics. The energies and transition probabilities for few-electron systems are evaluated. The line profile approach is also applied to the case of the quasidegenerate levels in highly charged ions. [Copyright &y& Elsevier]

Abstract: We present an accurate QED calculation of the interelectron interaction corrections to the energy of the (1s2p)1 P 1 and (1s2p)3 P 1 two-electron configurations for ions with nuclear charge 10⩽ Z ⩽92. When the fully relativistic treatment based on j–j coupling scheme is employed, the corresponding energy levels become quasidegenerate in the region Z ⩽40. To evaluate the energies of these configurations within the framework of QED we utilize the line profile approach. The numerical results we have obtained are compared with available experimental data and with different calculations. [Copyright &y& Elsevier]

Abstract: The second-order electron self-energy loop-after-loop correction is investigated for hydrogen-like ions in the region of low nuclear charge numbers Z. Both irreducible and reducible parts of this correction are evaluated for the 1s1/2-state within the Fried–Yennie gauge. We confirm the result obtained first by Mallampalli and Sapirstein. The reducible part of this correction is evaluated numerically for the first time and it is consistent with the corresponding analytical αZ-expansion. [Copyright &y& Elsevier]

The phenomenon of particle creation within a resonantly vibrating lossy cavity is investigated for the example of a massless scalar field at finite temperature. Leakage is provided by insertion of a dispersive mirror into a larger ideal cavity. Via the rotating wave approximation we demonstrate that for the case of parametric resonance the exponential growth of the number of created particles and the strong enhancement at finite temperatures are preserved in the presence of reasonable losses. The relevance for experimental tests of quantum radiation via the dynamical Casimir effect is addressed. [Copyright &y& Elsevier]

Ground‐state energies of the one‐ and two‐electron uranium dimers are calculated for internuclear distances in the range D=40–1,000 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, whereas the two‐photon‐exchange contribution is treated in the monopole approximation. [ABSTRACT FROM AUTHOR]

This review surveys the quantum theory of electromagnetic radiation for atomic systems. In particular, a review of current theoretical studies of multiphoton processes in one and two-electron atoms and highly charged ions is provided. Grounded on the quantum electrodynamics description the multiphoton transitions in presence of cascades, spin–statistic behaviour of equivalent photons and influence of external electric fields on multiphoton in atoms and anti-atoms are discussed. Finally, the nonresonant corrections which define the validity of the concept of the excited state energy levels are introduced. [ABSTRACT FROM AUTHOR]

We develop an efficient numerical implementation of the relativistic time-dependent density functional theory (RTDDFT) to study multielectron highly-charged ions subject to intense linearly-polarized laser fields. The interaction with the electromagnetic field is described within the electric dipole approximation. The resulting time-dependent relativistic Kohn–Sham (RKS) equations possess an axial symmetry and are solved accurately and efficiently with the help of the time-dependent generalized pseudospectral method. As a case study, we calculate multiphoton ionization probabilities of the neutral argon atom and argon-like xenon ion. Relativistic effects are assessed by comparison of our present results with existing non-relativistic data. [ABSTRACT FROM AUTHOR]

A new method for solving the time-dependent two-center Dirac equation is developed. The approach is based on the using of the finite basis of cubic Hermite splines on a three-dimensional lattice in the coordinate space. The relativistic calculations of the excitation and charge-transfer probabilities in the low-energy U 91 +(1 s)–U 92+ collisions in two and three dimensional approaches are performed. The obtained results are compared with our previous calculations employing the Dirac-Sturm basis sets [I.I. Tupitsyn et al., Phys. Rev. A 82, 042701 (2010)]. The role of the negative-energy Dirac spectrum is investigated within the monopole approximation. [ABSTRACT FROM AUTHOR]

The spectroscopical properties of hydrogen (H) and anti-hydrogen $(\bar{\rm H})$ atoms in external electric and magnetic fields are discussed. This problem became important in connection with the recent experimental success in production of $\bar{\rm H}$ atoms. The main features of these experiments are briefly reviewed. The proposals for the search of the CPT violation via comparison of the H and $\bar{\rm H}$ spectra are shortly discussed. The spectroscopical differences between H and $\bar{\rm H}$ atoms in external magnetic fields and in parallel magnetic and electric fields are described in detail. It is proven that the positions of the maxima of the frequency distributions for transition probabilities in external electric field for H and $\bar{\rm H}$ atoms will deviate if the non-resonant corrections to the Lorentz line profile are taken into account. [ABSTRACT FROM AUTHOR]

We report a theoretical treatment of the nuclear spin-dependent spatial parity nonconserving (NSD-PNC) electron–nuclear interaction effect in the diatomic homonuclear ortho-H 2 molecule. The magnetic dipole transition between v = 1 and v = 0 vibrational sublevels of the ground 1 Σ g + state is examined. The orthohydrogen molecule is a unique molecular system where the parity nonconserving (PNC) nuclear spin-dependent interaction due to the neutral weak currents can be directly observed and the corresponding coupling constant can be extracted from the future experiments. The theoretical simulation shows that using the cavity-enhanced scheme in conjunction with the record achievement of the intracavity absorption spectroscopy, the experiment on the observation of the NSD-PNC effect due to the neutral weak current in ortho-H 2 looks feasible. [ABSTRACT FROM AUTHOR]

Abstract: We consider single ionization of lithium atom in collisions with p and O8+ projectiles. Doubly differential cross sections for ionization are calculated within a relativistic non-perturbative approach. Comparisons with the recent measurements and theoretical predictions are made. Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: The probabilities of bound-free electron-positron pair creation are calculated for head-on collisions of bare uranium nuclei beyond the monopole approximation. The calculations are based on the numerical solving of the time-dependent Dirac equation in the target reference frame with multipole expansion of the projectile potential. In addition, the energy dependence of the pair-creation cross section is studied in the monopole approximation. Graphical abstract: [ABSTRACT FROM AUTHOR]