1,719 research outputs found
Quantal Two-Centre Coulomb Problem treated by means of the Phase-Integral Method II. Quantization Conditions in the Symmetric Case Expressed in Terms of Complete Elliptic Integrals. Numerical Illustration
The contour integrals, occurring in the arbitrary-order phase-integral
quantization conditions given in a previous paper, are in the first- and
third-order approximations expressed in terms of complete elliptic integrals in
the case that the charges of the Coulomb centres are equal. The evaluation of
the integrals is facilitated by the knowledge of quasiclassical dynamics. The
resulting quantization conditions involving complete elliptic integrals are
solved numerically to obtain the energy eigenvalues and the separation
constants of the and states of the hydrogen molecule ion
for various values of the internuclear distance. The accuracy of the formulas
obtained is illustrated by comparison with available numerically exact results.Comment: 19 pages, RevTeX 4, 4 EPS figures, submitted to J. Math. Phy
Theoretical and methodological grounds for the modernization of the tax administration system
The article stands for the theoretical underpinning of economic grounds of tax system and its building on the basis of social- and business-oriented socioeconomic features.
Authors proved the need for tax process management that represent the features of government-society-taxpayer relations with taxpayer’s leading role as macroeconomic tool for economic regulation process as well as providing the sustainable and balanced economic growth and innovative modernization of Russian economy.peer-reviewe
Double giant resonances in deformed nuclei
We report on the first microscopic study of the properties of two-phonon
giant resonances in deformed nuclei. The cross sections of the excitation of
the giant dipole and the double giant dipole resonances in relativistic heavy
ion collisions are calculated. We predict that the double giant dipole
resonance has a one-bump structure with a centroid 0.8 MeV higher than twice
energy for the single giant dipole resonance in the reaction under
consideration. The width of the double resonance equals to 1.33 of that for the
single resonance.Comment: 5 pages, 2 postscript figure
Self-consistent approach for the quantum confined Stark effect in shallow quantum wells
A computationally efficient, self-consistent complex scaling approach to
calculating characteristics of excitons in an external electric field in
quantum wells is introduced. The method allows one to extract the resonance
position as well as the field-induced broadening for the exciton resonance. For
the case of strong confinement the trial function is represented in factorized
form. The corresponding coupled self-consistent equations, which include the
effective complex potentials, are obtained. The method is applied to the
shallow quantum well. It is shown that in this case the real part of the
effective exciton potential is insensitive to changes of external electric
field up to the ionization threshold, while the imaginary part has
non-analytical field dependence and small for moderate electric fields. This
allows one to express the exciton quasi-energy at some field through the
renormalized expression for the zero-field bound state.Comment: 13 pages, RevTeX4, 6 figure
Optical models of the molecular atmosphere
The use of optical and laser methods for performing atmospheric investigations has stimulated the development of the optical models of the atmosphere. The principles of constructing the optical models of molecular atmosphere for radiation with different spectral composition (wideband, narrowband, and monochromatic) are considered in the case of linear and nonlinear absorptions. The example of the development of a system which provides for the modeling of the processes of optical-wave energy transfer in the atmosphere is presented. Its physical foundations, structure, programming software, and functioning were considered
Search for weak M1 transitions in Ca with inelastic proton scattering
The spinflip M1 resonance in the doubly magic nucleus Ca, dominated by
a single transition, serves as a reference case for the quenching of
spin-isospin modes in nuclei. The aim of the present work is a search for weak
M1 transitions in Ca with a high-resolution (p,p') experiment at 295 MeV
and forward angles including 0 degree and a comparison to results from a
similar study using backward-angle electron scattering at low momentum
transfers in order to estimate their contribution to the total B(M1) strength.
M1 cross sections of individual peaks in the spectra are deduced with a
multipole decomposition analysis. The corresponding reduced B(M1) transition
strengths are extracted following the approach outlined in J. Birkhan et al.,
Phys. Rev. C 93, 041302(R) (2016). In total, 29 peaks containing a M1
contribution are found in the excitation energy region 7 - 13 MeV. The
resulting B(M1) strength distribution compares well to the electron scattering
results considering different factors limiting the sensitivity in both
experiments and the enhanced importance of mechanisms breaking the
proportionality of nuclear cross sections and electromagnetic matrix elements
for weak transitions as studied here. The total strength of 1.19(6)
deduced assuming a non-quenched isoscalar part of the (p,p') cross sections
agrees with the (e,e') result of 1.21(13) . A binwise analysis above
10 MeV provides an upper limit of 1.62(23) . The present results
confirm that weak transitions contribute about 25% to the total B(M1) strength
in Ca and the quenching factors of GT and spin-M1 strength are
comparable in fp-shell nuclei. Thus, the role of of meson exchange currents
seems to be neglible, in contrast to sd-shell nuclei.Comment: 11 pages, 9 figures, revised analysis with oxygen contamination
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Photoluminescence Spectroscopy of the Molecular Biexciton in Vertically Stacked Quantum Dot Pairs
We present photoluminescence studies of the molecular neutral
biexciton-exciton spectra of individual vertically stacked InAs/GaAs quantum
dot pairs. We tune either the hole or the electron levels of the two dots into
tunneling resonances. The spectra are described well within a few-level,
few-particle molecular model. Their properties can be modified broadly by an
electric field and by structural design, which makes them highly attractive for
controlling nonlinear optical properties.Comment: 4 pages, 5 figures, (v2, revision based on reviewers comments,
published
Spin Fine Structure in Optically Excited Quantum Dot Molecules
The interaction between spins in coupled quantum dots is revealed in distinct
fine structure patterns in the measured optical spectra of InAs/GaAs double
quantum dot molecules containing zero, one, or two excess holes. The fine
structure is explained well in terms of a uniquely molecular interplay of spin
exchange interactions, Pauli exclusion and orbital tunneling. This knowledge is
critical for converting quantum dot molecule tunneling into a means of
optically coupling not just orbitals, but spins.Comment: 10 pages, 7 figures, added material, (published
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