2,497 research outputs found
Isotope shifts of the 2-2 transition in B-like ions
Isotope shifts of the 2-2 transition in B-like ions are
evaluated for a wide range of the nuclear charge number: Z=8-92. The
calculations of the relativistic nuclear recoil and nuclear size effects are
performed using a large scale configuration-interaction Dirac-Fock-Sturm
method. The corresponding QED corrections are also taken into account. The
results of the calculations are compared with the theoretical values obtained
with other methods. The accuracy of the isotope shifts of the
2-2 transition in B-like ions is significantly improved.Comment: arXiv admin note: text overlap with arXiv:1410.707
Localization properties of a one-dimensional tight-binding model with non-random long-range inter-site interactions
We perform both analytical and numerical studies of the one-dimensional
tight-binding Hamiltonian with stochastic uncorrelated on-site energies and
non-fluctuating long-range hopping integrals . It was argued recently [A.
Rodriguez at al., J. Phys. A: Math. Gen. 33, L161 (2000)] that this model
reveals a localization-delocalization transition with respect to the disorder
magnitude provided . The transition occurs at one of the band edges (the upper
one for and the lower one for). The states at the other band edge are always
localized, which hints on the existence of a single mobility edge. We analyze
the mobility edge and show that, although the number of delocalized states
tends to infinity, they form a set of null measure in the thermodynamic limit,
i.e. the mobility edge tends to the band edge. The critical magnitude of
disorder for the band edge states is computed versus the interaction exponent
by making use of the conjecture on the universality of the normalized
participation number distribution at transition.Comment: 7 pages, 6 postscript figures, uses revtex
Ground state of superheavy elements with : systematic study of the electron-correlation, Breit, and QED effects
For superheavy elements with atomic numbers , the concept
of the ground-state configuration is being reexamined. To this end,
relativistic calculations of the electronic structure of the low-lying levels
are carried out by means of the Dirac-Fock and configuration-interaction
methods.The magnetic and retardation parts of the Breit interaction as well as
the QED effects are taken into account. The influence of the relativistic, QED,
and electron-electron correlation effects on the determination of the
ground-state is analyzed
Relativistic calculations of the energies of the low-lying , , states and the probabilities of the one-photon transitions in heliumlike uranium
For heliumlike uranium, the energies of the singly-excited , ,
and states with and the probabilities of the one-photon
, , and transitions
are evaluated. The calculations are performed within the Breit approximation
using the configuration-interaction method in the basis of the Dirac-Fock-Sturm
orbitals. The QED corrections to the energy levels are calculated employing the
model-QED-operator approach. The nuclear recoil, frequency-dependent
Breit-interaction, nuclear polarization, and nuclear deformation corrections
are taken into account as well
Superradiance from an ultrathin film of three-level V-type atoms: Interplay between splitting, quantum coherence and local-field effects
We carry out a theoretical study of the collective spontaneous emission
(superradiance) from an ultrathin film comprised of three-level atoms with
-configuration of the operating transitions. As the thickness of the system
is small compared to the emission wavelength inside the film, the local-field
correction to the averaged Maxwell field is relevant. We show that the
interplay between the low-frequency quantum coherence within the subspace of
the upper doublet states and the local-field correction may drastically affect
the branching ratio of the operating transitions. This effect may be used for
controlling the emission process by varying the doublet splitting and the
amount of low-frequency coherence.Comment: 15 pages, 5 figure
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