Electrodynamic Effects Research Articles

The van der Waals interactions in systems involving superheavy elements: the case of oganesson (Z = 118).

This work presents a study involving dimers composed of He, Ne, Ar, Kr, Xe, Rn, and Og noble gases with oganesson, a super-heavy closed-shell element (Z = 118). He-Og, Ne-Og, Ar-Og, Kr-Og, Xe-Og, Rn-Og, and Og-Og ground state electronic potential energy curves were calculated based on the 4-component (4c) Dirac-Coulomb Hamiltonian and were counterpoise corrected. For the 4c calculations, the electron correlation was taken into account using the same methodology (MP2-srLDA) and basis set quality (Dyall's acv3z and Dunning's aug-cc-PVTZ). All calculations included quantum electrodynamics effects at the Gaunt interaction level. For all the aforementioned dimers the vibration energies, spectroscopic constants (ωe, ωexe, ωeye, αe, and γe), and lifetime as a function of the temperature (which ranged from 200 to 500 K) were also calculated. The obtained results suggest that the inclusion of quantum electrodynamics effects reduces the value of the dissociation energy of all hetero-nuclear molecules with a percentage contribution ranging from 0.48% (for the He-Og dimer) to 9.63% (for the Rn-Og dimer). The lifetime calculations indicate that the Og-He dimer is close to the edge of instability and that Ng-Og dimers are relatively less stable when the Gaunt correction is considered. Exploiting scaling laws that adopt the polarizability of involved partners as scaling factors, it has also been demonstrated that in such systems the interaction is of van der Waals nature (size repulsion plus dispersion attraction) and this permitted an estimation of dissociation energy and equilibrium distance in the Og-Og dimer. This further information has been exploited to evaluate the rovibrational levels in this symmetric dimer and to cast light on the macroscopic properties of condensed phases concerning the complete noble gas family, emphasizing some anomalies of Og.

Generalized relativistic small‐core pseudopotentials accounting for quantum electrodynamic effects: Construction and pilot applications

AbstractA simple procedure to incorporate one‐loop quantum electrodynamic (QED) corrections into the generalized (Gatchina) nonlocal shape‐consistent relativistic pseudopotential model is described. The pseudopotentials for Lu, Tl, and Ra replacing only inner core shells (with principal quantum numbersn ≤ 3 for the two former elements andn ≤ 4 for the latter one) are derived from the solutions of reference atomic SCF problems with the Dirac–Coulomb–Breit Hamiltonian to which the model Lamb shift operator added. QED contributions to atomic valence excitation energies evaluated at the SCF level are demonstrated to exceed the errors introduced by the pseudopotential approximation itself by an order of magnitude. Pilot applications of the new model to calculations of excitation energies of two‐valence‐electron atomic systems using the intermediate‐Hamiltonian relativistic Fock space coupled cluster method reformulated here for incomplete main model spaces are reported. Implications for high‐accuracy molecular excited state calculations are discussed.

Perspective: Simultaneous treatment of relativity, correlation, and QED

AbstractElectronic structure calculations of many‐electron systems should in principle treat relativistic, correlation, and quantum electrodynamics (QED) effects simultaneously to a high precision, so as to match experimental measurements as close as possible. While both relativistic and QED effects can readily be built into the many‐electron Hamiltonian, electron correlation is more difficult to describe due to the exponential growth of the number of parameters in the wave function. Compared with the spin‐free case, spin–orbit interaction results in the loss of spin symmetry and concomitant complex algebra, thereby rendering the treatment of electron correlation even more difficult. Possible solutions to these issues are highlighted here.This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods

Achieving relativistically intense X-rays from structured plasma lens

Focusing of high-power X-rays is still a great challenge and the intensity of X-ray attained in existing focusing schemes is still far below the relativistic threshold. Here, we propose that solid density plasma lens can potentially focus X-ray lasers at very high power levels. The interaction of high-power X-ray laser with solid-density plasmas is systematically studied. It is theoretically shown that there exists a certain range of wavelengths for X-ray lasers that can be focused in solid-density plasmas when the input power and plasma density are determined. To avoid the essential laser-plasma instabilities and obtain high-gain intensity amplification for X-ray, we design concave structured plasma lens. Particle-in-cell simulation results show that such regime can effectively avoid the instabilities and focus X-ray of micrometer-sized spot and multi-TW power, and thus lead to the generation of relativistic intensity X-ray. The parameters of the concave structures and the effects of quantum electrodynamics are also discussed and it indicates that our scheme is quite robust. We further demonstrate that the relativistic X-ray laser interacting with thin-foil leads to high-quality attosecond electron bunches.

Weak lensing, Hawking radiation and greybody factor bound by a charged black holes with non-linear electrodynamics corrections

In this paper, we study gravitational lensing in the weak field limits and the shadow by charged black holes in non-linear electrodynamics corrections. To find the deflection angle in vacuum (non-plasma) up to the leading order terms, we compute the optical Gaussian curvature from optical metric and utilize the Gauss–Bonnet theorem by applying Gibbons and Werner’s technique. Also, we derive the bending angle in plasma and dark matter mediums and observe that the bending angle increases by increasing the effects of these mediums. Further, in vacuum and plasma mediums, we investigate the graphical behavior of the bending angle with respect to the impact parameter u and notice that the bending angle exponentially decreases. Moreover, we calculate the Hawking temperature using the Gauss–Bonnet theorem and compare it with a standard method of computing the Hawking temperature. Furthermore, we investigate the bound of the greybody factor and graphically examine that bound converges to the 1. We relate our obtained results with the results of black holes given in the literature. Finally, we have considered exploring the effect of non-linear electrodynamics (NLED), plasma and dark matter on the black hole’s shadow radius to broaden the study’s scope. Results for the shadow indicate that the three parameters give different deviations to the shadow radius. Interestingly, while plasma affects both the photonsphere and shadow, dark matter only influences the shadow.

Excitation energies, lifetimes, and transition data for Zr XXIX

The energies and lifetimes of the lowest 303 fine-structure levels belonging to the 3s2, 3s3p, 3s3d, 3p3d, 3d2, 3snl (n = 4 − 6; l = 0 − 5), 3pnl (n = 4 − 5; l = 0 − 4), 3p6s, and 3dnl (n = 4 − 5; l = 0 − 4) configurations of Mg-like zirconium, Zr XXIX, are calculated using the relativistic multiconfiguration Dirac-Hartree-Fack (MCDHF) method employed in the GRASP2018 atomic structure computer package. The MCDHF wavelengths, transition probabilities, weighted oscillator strengths, and line strengths for the electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) transitions between the levels considered are presented. The Breit-interaciton (BI) and quantum electrodynamics (QED) effects are considered in the computations. Comparisons with available experimental and other theoretical data are carried out to evaluate the accuracy of the present results.

Extended Calculations of Atomic Structure Parameters for Na-like Ar, Kr and Xe Ions Using Relativistic MCDHF and MBPT Methods

In this study, comprehensive calculations of energies, hyperfine structure constants, Landé gJ factors and isotope shifts have been performed for the lowest 71 states of Na-like Ar7+, Kr25+ and Xe43+ ions. Radiative parameters viz., wavelengths, transition rates, oscillator strengths and lifetimes are estimated for the electric dipole E1 transitions among these levels. The states under consideration include 1s22s22p6nl for n = 3–9, l = 0–6, and the fully relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) method integrated in the latest version of the general-purpose relativistic atomic structure package (GRASP2018) is used for the calculations. The additional corrections, such as the Breit interaction and quantum electrodynamics effects are included in the relativistic configuration interaction calculations, and their effects on energies and other parameters are analysed. We examined the impact of including the core–core and core–valence correlations on level energies. Furthermore, to inspect the reliability of our MCDHF results, we performed another set of calculations using the many-body perturbation theory built into the Flexible Atomic Code (FAC). Moreover, we estimated the uncertainties in the computed lifetimes and transition parameters and assigned their accuracy class. A thorough comparison between the two obtained calculations and with the previous theoretical and experimental results, wherever available, is carried out and a good agreement is observed.

Effect of nonlinear electrodynamics on shadows of slowly rotating black holes* *Supported by the National Key R&D Program of China (2020YFC2201400)

In this study, we investigate the effect of nonlinear electrodynamics on the shadows of charged, slowly rotating black holes with the presence of a cosmological constant. Rather than the null geodesic of the background black hole spacetime, the trajectory of a photon, as a perturbation of the nonlinear electrodynamic field, is governed by an effective metric. The latter can be derived by analyzing the propagation of a discontinuity of the electromagnetic waveform. Subsequently, the image of the black hole and its shadow can be evaluated using the backward ray-tracing technique. We explore the properties of the resultant black hole shadows of two different scenarios of nonlinear electrodynamics, namely, the logarithmic and exponential forms. In particular, the effects of nonlinear electrodynamics on the optical image are investigated, as well as the image's dependence on other metric parameters, such as the black hole spin and charge. The resulting black hole image and shadow display rich features that potentially lead to observational implications.

Implications of gauge freedom for nonrelativistic quantum electrodynamics

Gauge freedom in quantum electrodynamics (QED) outside of textbook regimes is reviewed. It is emphasized that QED subsystems are defined relative to a choice of gauge. Each definition uses different gauge-invariant observables. This relativity is eliminated only if a sufficient number of Markovian and weak-coupling approximations are employed. All physical predictions are gauge invariant, including subsystem properties such as photon number and entanglement. However, subsystem properties naturally differ for different physical subsystems. Gauge ambiguities arise not because it is unclear how to obtain gauge-invariant predictions, but because it is not always clear which physical observables are the most operationally relevant. The gauge invariance of a prediction is necessary but not sufficient to ensure its operational relevance. It is shown that, in controlling which gauge invariant observables are used to define a material system, the choice of gauge affects the balance between the material system's localization and its electromagnetic dressing. Various implications of subsystem gauge relativity for deriving effective models, for describing time-dependent interactions, for photodetection theory, and for describing matter within a cavity are reviewed.

Microwave mode cooling and cavity quantum electrodynamics effects at room temperature with optically cooled nitrogen-vacancy center spins

Recent experimental and theoretical studies demonstrated microwave mode cooling and cavity quantum electrodynamics (C-QED) effects at room temperature by using optically cooled nitrogen-vacancy (NV) spins. In this article, we consider improvements of these effects by exploring parameters in recent diamond maser experiments with a high frequency microwave resonator. By accounting for the rich electronic and spin levels, we provide a more complete treatment of optical pumping and dissipation in NV centers, and study the dependence of system performance on laser power. We predict the reduction of microwave photon number down to 261 (equivalent to a temperature of 116 K), about five times lower than the values reported recently. We also predict the laser-power controlled C-QED effects across weak-to-strong coupling regimes, and observe saturation of these effects under strong laser pumping. Our model can be modified straightforwardly to investigate similar effects with other solid-state spins and possible C-QED effects in maser operation.

Review of rationales for the introduction of the “Geophysical electrodynamics” term

Background. The article provides arguments for the introduction of the “geophysical electrodynamics” term.Aim. To justify the introduction of a new term “geophysical electrodynamics”.Methods of substantiation. The limits of the applicability of Maxwell’s equations are studied. Additionally, some concepts are introduced, in particular, about a new paradigm in electrodynamics, about new equations in geophysical electrodynamics, about the differences between new electrodynamics and Maxwell’s electrodynamics, about the sources of toroidal and poloidal electromagnetic fields, about toroidal currents in Maxwell’s equations, about non-power electromagnetic fields, about the quantum effect in non-power electromagnetic fields, toroidal fields in the core of the Earth, mathematical achievements in the new paradigm, about the reproduction of sources of the electromagnetic field of the Earth, and effects in classical electrodynamics explained by geophysical electrodynamics.Results. Responses to the above justifications were received.Conclusion. Physical and mathematical justifications for the introduction of the term “geophysical electrodynamics” find confirmation both in the natural electromagnetic field of the Earth, and in a number of long-known classical effects in the standard Maxwell’s electrodynamics. Small but fundamental differences of one electrodynamics from another will reduce the number of effects unexplained from the standpoint of Maxwell’s equations, encountered in both theory and experiments on Earth.

Quantum electrodynamics of two-body systems with arbitrary masses up to α6 order

We perform a calculation of quantum electrodynamics effects in excited states with $l>1$ of arbitrary two-body systems up to $\alpha^6\,\mu$ order. The obtained results are valid for hadronic atoms, as long as the strong interaction effects are negligible. We demonstrate that for circular states with $l\sim n$, the effective expansion parameter is $Z\,\alpha/n$, which extends the applicability of the derived formulas to heavy ions. Moreover, inclusion of higher-order terms is feasible, which indicates that accurate measurements of excited states of, for example, muonic or antiprotonic hydrogenic ions can be used to determine the fundamental constants and to search for the existence of yet unknown long-range interactions.

Charged particle motion and radiation in strong electromagnetic fields

The dynamics of charged particles in electromagnetic fields is an essential component of understanding the most extreme environments in our Universe. In electromagnetic fields of sufficient magnitude, radiation emission dominates the particle motion and effects of nonlinear quantum electrodynamics (QED) are crucial, which triggers electron-positron pair cascades and counterintuitive particle-trapping phenomena. As a result of recent progress in laser technology, high-power lasers provide a platform to create and probe such fields in the laboratory. With new large-scale laser facilities on the horizon and the prospect of investigating these hitherto unexplored regimes, we review the basic physical processes of radiation reaction and QED in strong fields, how they are treated theoretically and in simulation, the new collective dynamics they unlock, recent experimental progress and plans, as well as possible applications for high-flux particle and radiation sources.

QED effects at grazing incidence on solid-state targets

New laser facilities will reach intensities of 10^{23} text {W cm}^{-2}. This advance enables novel experimental setups in the study of laser–plasma interaction. In these setups with extreme fields, quantum electrodynamic (QED) effects such as photon emission via nonlinear Compton scattering and Breit–Wheeler pair production become important. We study high-intensity lasers grazing the surface of a solid-state target by two-dimensional particle-in-cell simulations with QED effects included. The two laser beams collide at the target surface at a grazing angle. Due to the fields near the target surface, electrons are extracted and accelerated. Finally, the extracted electrons collide with the counter-propagating laser, which triggers many QED effects and leads to a QED cascade under a sufficient laser intensity. Here, the processes are studied for various laser intensities and angle of incidence and finally compared with a seeded vacuum cascade. Our results show that the proposed target can yield many orders of magnitude more secondary particles and develop a QED cascade at lower laser intensities than the seeded vacuum alone.

Nonlinear Compton scattering in time-dependent electric fields beyond the locally constant crossed field approximation

Locally constant crossed field approximation (LCFA) is a powerful tool for theoretical and numerical studies of various strong field quantum electrodynamical effects. We explore this approximation in detail for photon emission by a spinless particle in a strong time-dependent electric field. This kind of electromagnetic fields is of particular interest, because, in contrast to the comprehensively studied case of a plane wave, they are not crossed. We develop an approach for calculating photon emission probability in a generic time-dependent electric field, establish the range of applicability of LCFA, and calculate the corrections to it.

Rapid Volcanic Modification of the E‐Region Dynamo: ICON's First Glimpse of the Tonga Eruption

AbstractThe 15 January 2022 Hunga Tonga‐Hunga Ha'apai volcano eruption drove global atmospheric waves that propagated into space and impacted the ionosphere. Here we show immediate large‐scale electrodynamic effects of the eruption using observations from the National Aeronautics and Space Administration's Ionospheric Connection Explorer. We report extreme zonal and vertical ion drifts thousands of kilometers away from Tonga within an hour of the eruption, before the arrival of any atmospheric wave. The measured drifts were magnetically connected to the ionospheric E‐region just 400 km from Tonga, suggesting that the expanding wavefront created strong electric potentials which were transmitted along Earth's magnetic field. A simple theoretical model suggests that the observed drifts are consistent with an expanding wave with a large (>200 m/s) neutral wind amplitude. These observations are the first direct detection in space of the immediate electrodynamic effects of a volcanic eruption and will help constrain future models of impulsive lower atmospheric events.

Theoretical calculations on Landé g-factors and quadratic Zeeman shift coefficients of nsnp clock states in Mg and Cd optical lattice clocks

The study of magnetic field effects on the clock transition of Mg and Cd optical lattice clocks is scarce. In this work, the hyperfine-induced Landé g-factors and quadratic Zeeman shift coefficients of the nsnp clock states for 111,113Cd and 25Mg were calculated by using the multi-configuration Dirac–Hartree–Fock theory. To obtain accurate values of these parameters, the impact of electron correlations and furthermore the Breit interaction and quantum electrodynamical effects on the Zeeman and hyperfine interaction matrix elements, and energy separations were investigated in detail. We also estimated the contributions from perturbing states to the Landé g-factors and quadratic Zeeman shift coefficients concerned so as to truncate the summation over the perturbing states without loss of accuracy. Our calculations provide important data for estimating the first- and second-order Zeeman shifts of the clock transition for the Cd and Mg optical lattice clocks.

Generation of collimated vortex gamma-rays from intense Poincaré beam–plasma interaction

We report on numerical calculations in which a multi-petawatt γ-ray beam is generated using a novel configuration based on fully structured light irradiating an overdense plasma waveguide. We analyze how the relativistic laser pulse efficiently confines and accelerates plasma electrons to GeV-scale energies and drives a quasi-static field that induces magneto-bremsstrahlung radiation. Multiphoton Compton scattering of electrons in the intense part of the laser also occurs although the radiated energy-density is comparatively lower. The emitted γ-rays carry orbital angular momentum, are highly collimated, and account for upwards of 15% of the incident field energy in one particular case. A comparison of the laser-to-particle angular momentum and energy transfer efficiencies is made between the cases of irradiation by a circularly polarized Laguerre–Gauss mode and one type of full Poincaré beam, and it is found that the latter yields an order-of-magnitude enhancement. The essential characteristics of the interaction are validated with three-dimensional particle-in-cell simulations that include quantum electrodynamical effects.

QED and accretion flow models effect on optical appearance of Euler–Heisenberg black holes

Taking the quantum electrodynamics (QED) effect into account, we investigate the geometrical-optics appearance of the Euler–Heisenberg (EH) black hole (BH) under the different accretion flows context, which depends on the BH space-time structure and different sources of light. The more significant magnetic charge leads to the smaller shadow radius for the EH BH, while the different values of the EH parameter do not ruin it. Different features of the corresponding two-dimensional shadow images are derived for the three optically thin accretion flow models. It is shown that the total observed intensity in the static spherical accretion flow scenario leads than that of the infalling spherical accretion flow under same parameters, but the size and position of the EH BH shadows do not change in both of these accretions flows, implying that the BH shadow size depends on the geometric space-time and the shadows luminosities rely on the accretion flow morphology. Of particular interest is that a thin disk accretion model illuminated the BH, we found that the contribution of the lensing ring to the total observed flux is less than 5%, and the photon ring is less than 2%, indicating that the direct emission dominates the optical appearance of the EH BH. It is also believed that the optical appearance of the BH image depends on the accretion disk radiation position in this scenario, which can serve as a probe for the disk structure around the active galactic nucleus (AGN) of M87^{*} like.

QED effects on phase transition and Ruppeiner geometry of Euler-Heisenberg-AdS black holes* *Supported by the National Natural Science Foundation of China (12075103, 11675064, 12047501) and the 111 Project (B20063)

Considering the quantum electrodynamics (QED) effect, we study the phase transition and Ruppeiner geometry of Euler-Heisenberg anti-de Sitter black holes in the extended phase space. For negative and small positive QED parameters, we observe a small/large black hole phase transition and reentrant phase transition, respectively, whereas a large positive value of the QED parameter ruins the phase transition. Phase diagrams for each case are explicitly shown. Then, we construct the Ruppeiner geometry in thermodynamic parameter space. Different features of the corresponding scalar curvature are shown for both the small/large black hole phase transition and reentrant phase transition cases. Of particular interest is the additional region of positive scalar curvature, indicating a dominant repulsive interaction among black hole microstructures, for the black hole with a small positive QED parameter. Furthermore, universal critical phenomena are observed for the scalar curvature of Ruppeiner geometry. These results indicate that the QED parameter has a crucial influence on the black hole phase transition and microstructure.