9,840 research outputs found
Accounting for correlations with core electrons by means of the generalized relativistic effective core potentials: Atoms Hg and Pb and their compounds
A way to account for correlations between the chemically active (valence) and
innermore (core) electrons in the framework of the generalized relativistic
effective core potential (GRECP) method is suggested. The "correlated" GRECP's
(CGRECP's) are generated for the Hg and Pb atoms. Only correlations for the
external twelve and four electrons of them, correspondingly, should be treated
explicitly in the subsequent calculations with these CGRECP's whereas the
innermore electrons are excluded from the calculations. Results of atomic
calculations with the correlated and earlier GRECP versions are compared with
the corresponding all-electron Dirac-Coulomb values. Calculations with the
above GRECP's and CGRECP's are also carried out for the lowest-lying states of
the HgH molecule and its cation and for the ground state of the PbO molecule as
compared to earlier calculations and experimental data. The accuracy for the
vibrational frequencies is increased up to an order of magnitude and the errors
for the bond lengths (rotational constants) are decreased in about two times
when the correlated GRECP's are applied instead of earlier GRECP versions
employing the same innercore-outercore-valence partitioning.Comment: 12 pages, 4 tables, the text of the paper was significantly improve
Electromagnetic modulation of monochromatic neutrino beams
A possibility to produce a modulated monochromatic neutrino beam is
discussed. Monochromatic neutrinos can be obtained in electron capture by
nuclei of atoms or ions, in particular, by nuclei of hydrogen-like ions. It is
shown that monochromatic neutrino beam from such hydrogen-like ions with nuclei
of non-zero spin can be modulated because of different probabilities of
electron capture from hyperfine states. Modulation arises by means of inducing
of electromagnetic transitions between the hyperfine states. Requirements for
the hydrogen-like ions with necessary properties are discussed. A list of the
appropriate nuclei for such ions is presented.Comment: 11 pages, 1 figure, minor corrections to match the final published
versio
In-medium modification and decay asymmetry of omega mesons in cold nuclear matter
We discuss an asymmetry of the decay in nuclear matter with
respect to the electron and positron energies. This asymmetry is sensitive to
the properties of the meson self-energy and, in particular, it has a
non-trivial dependence on the energy and momentum. Therefore, this
asymmetry may serve as a powerful tool in studying the properties of the
meson in the nuclear medium.Comment: 19 pages, 9 figure
Selected vector-meson decay-distributions in reactions of polarized photons with protons
We develop a formalism for studying vector meson () photo-production at
the proton () with polarized photons, , through an
analysis of the decay distribution in the channel . We show
that this decay distribution differs noticeably from the distributions of
purely hadronic decays, like , .
Formulas for the decay distributions are presented which are suitable for data
analysis and interpretation.Comment: 3 pages, 2 figure
Isoscalar-Isovector Interferences in Reactions as a Probe of Baryon Resonance Dynamics
The isoscalar-isovector () interferences in the exclusive
reactions and near the
threshold leads to a distinct difference of the dielectron invariant mass
distributions depending on beam energy. The strength of this effect is
determined by the coupling of resonances to the nucleon vector-meson channels
and other resonance properties. Therefore, a combined analysis of these
reactions can be used as a tool for determining the baryon resonance dynamics
Microscopic theory of spin-orbit torques and skyrmion dynamics
We formulate a general microscopic approach to spin-orbit torques in thin
ferromagnet/heavy-metal bilayers in linear response to electric current or
electric field. The microscopic theory we develop avoids the notion of spin
currents and spin-Hall effect. Instead, the torques are directly related to a
local spin polarization of conduction electrons, which is computed from
generalized Kubo-St\v{r}eda formulas. A symmetry analysis provides a one-to-one
correspondence between polarization susceptibility tensor components and
different torque terms in the Landau-Lifshitz-Gilbert equation for
magnetization dynamics. The spin-orbit torques arising from Rashba or
Dresselhaus type of spin-orbit interaction are shown to have different
symmetries. We analyze these spin-orbit torques microscopically for a generic
electron model in the presence of an arbitrary smooth magnetic texture. For a
model with spin-independent disorder we find a major cancelation of the
torques. In this case the only remaining torque corresponds to the
magnetization-independent Edelstein effect. Furthermore, our results are
applied to analyze the dynamics of a Skyrmion under the action of electric
current.Comment: 13 pages, 4 figure
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