Search

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]

The rigorous two-center approach based on the dual-kinetically balanced finite-basis-set expansion is applied to one-electron, heteronuclear diatomic Bi-Au, U-Pb, and Cf-U quasimolecules. The obtained 1 σ ground-state energies are compared with previous calculations, when possible. Upon analysis of three different placements of the coordinate system's origin in the monopole approximation of the two-center potential: (1) in the middle, between the nuclei, (2) in the center of the heavy nucleus, and (3) in the center of the light nucleus, a substantial difference between the results is found. The leading contributions of one-electron quantum electrodynamics (self-energy and vacuum polarization) are evaluated within the monopole approximation as well. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

The generalized dual-kinetic-balance approach for axially symmetric systems is employed to solve the two-center Dirac problem. The spectra of one-electron homonuclear quasimolecules are calculated and compared with the previous calculations. The analysis of the monopole approximation with two different choices of the origin is performed. Special attention is paid to the lead and xenon dimers, Pb 82 + –Pb 82 + –e − and Xe 54 + –Xe 54 + –e − , where the energies of the ground and several excited σ -states are presented in the wide range of internuclear distances. The developed method provides the quasicomplete finite basis set and allows for the construction of perturbation theory, including within the bound-state QED. [ABSTRACT FROM AUTHOR]

Doubly differential cross sections for projectile ionization in fast collisions of few-electron uranium ions with the nitrogen target are calculated within the first order of the relativistic perturbation theory. A comparison with the recent measurements of the energy distribution of forward-emitted electrons is made and good agreement is found. [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]

Potential energy curves for excited leptonic states of the helium-antihydrogen system are calculated within the Ritz variational approach. An explicitly correlated ansatz for the leptonic wave function is employed describing accurately the motion of the leptons (two electrons and positron) in the field of the helium nucleus and of the antiproton with an arbitrary orbital angular momentum projection Lambda onto the internuclear axis. Results for Lambda=0, 1, and 30 are presented. For quasibound states with large values of Lambda and rotational quantum numbers J>Lambda no annihilation and rearrangement decay channels occur; i.e., they are metastable.

Motivated by a recent proposal for an experimental verification of the dynamical Casimir effect, the macroscopic electromagnetic field within a perfect cavity containing a thin slab with a time-dependent dielectric permittivity is quantized in terms of the dual potentials. For the resonance case, the number of photons created out of the vacuum due to the dynamical Casimir effect is calculated for both polarizations. It turns out that only TM modes can be excited efficiently.

As an alternative to the sonic black hole analogs we discuss a different scenario for modeling the Schwarzschild geometry in a laboratory--the dielectric black hole. The dielectric analog of the horizon occurs if the velocity of a medium with a finite permittivity exceeds the speed of light in that medium. The relevance for experimental tests of the Hawking effect and possible implications are addressed.