1,559 research outputs found
Relativistic corrections to the nuclear Schiff moment
Parity and time invariance violating (-odd) atomic electric dipole
moments (EDM) are induced by interaction between atomic electrons and nuclear
-odd moments which are produced by -odd nuclear forces. The nuclear
EDM is screened by atomic electrons. The EDM of a non-relativistic atom with
closed electron subshells is induced by the nuclear Schiff moment. For heavy
relativistic atoms EDM is induced by the nuclear local dipole moments which
differ by 10-50% from the Schiff moments calculated previously.
We calculate the local dipole moments for and where the most accurate atomic and molecular EDM measurements have been
performed.Comment: 3 pages, no figures, brief repor
The anisotropic Heisenberg chain in coexisting transverse and longitudinal magnetic fields
The one-dimensional spin-1/2 model in a mixed transverse and
longitudinal magnetic field is studied. Using the specially developed version
of the mean-field approximation the order-disorder transition induced by the
magnetic field is investigated. The ground state phase diagram is obtained. The
behavior of the model in low transverse field is studied on the base of
conformal field theory. The relevance of our results to the observed phase
transition in the quasi-one-dimensional antiferromagnet is
discussed.Comment: 18 pages, 6 figure
Translationally invariant nonlinear Schrodinger lattices
Persistence of stationary and traveling single-humped localized solutions in
the spatial discretizations of the nonlinear Schrodinger (NLS) equation is
addressed. The discrete NLS equation with the most general cubic polynomial
function is considered. Constraints on the nonlinear function are found from
the condition that the second-order difference equation for stationary
solutions can be reduced to the first-order difference map. The discrete NLS
equation with such an exceptional nonlinear function is shown to have a
conserved momentum but admits no standard Hamiltonian structure. It is proved
that the reduction to the first-order difference map gives a sufficient
condition for existence of translationally invariant single-humped stationary
solutions and a necessary condition for existence of single-humped traveling
solutions. Other constraints on the nonlinear function are found from the
condition that the differential advance-delay equation for traveling solutions
admits a reduction to an integrable normal form given by a third-order
differential equation. This reduction also gives a necessary condition for
existence of single-humped traveling solutions. The nonlinear function which
admits both reductions defines a two-parameter family of discrete NLS equations
which generalizes the integrable Ablowitz--Ladik lattice.Comment: 24 pages, 4 figure
Nonlinear Lattices Generated from Harmonic Lattices with Geometric Constraints
Geometrical constraints imposed on higher dimensional harmonic lattices
generally lead to nonlinear dynamical lattice models. Helical lattices obtained
by such a procedure are shown to be described by sine- plus linear-lattice
equations. The interplay between sinusoidal and quadratic potential terms in
such models is shown to yield localized nonlinear modes identified as intrinsic
resonant modes
FEATURES OF THE CEPHALOMETRIC PROFILE OF UKRAINIAN YOUTH BY METHODS OF RICKETTS R. M., BURSTONE C. J. AND HARVOLD E. P.
In the article, on the basis of the previous metric characteristics of craniofacial structures using methods of Ricketts R. M., Burstone C. J. and Harvold E. P. in Ukrainian young men and women with orthognathic bite, the features of the cephalometric profile of Ukrainian young men and women were analyzed in comparison with the values of analogical indices of the data determined by the authors of these techniques on residents of other populations and ethnic groups. The established features of the cephalometric characteristics of the juvenile Ukrainian population confirm the need for the creation and further study of normative cephalometric data for various ethnic, age and gender groups of the population.In the article, on the basis of the previous metric characteristics of craniofacial structures using methods of Ricketts R. M., Burstone C. J. and Harvold E. P. in Ukrainian young men and women with orthognathic bite, the features of the cephalometric profile of Ukrainian young men and women were analyzed in comparison with the values of analogical indices of the data determined by the authors of these techniques on residents of other populations and ethnic groups. The established features of the cephalometric characteristics of the juvenile Ukrainian population confirm the need for the creation and further study of normative cephalometric data for various ethnic, age and gender groups of the population
Orbital glass and spin glass states of 3He-A in aerogel
Glass states of superfluid A-like phase of 3He in aerogel induced by random
orientations of aerogel strands are investigated theoretically and
experimentally. In anisotropic aerogel with stretching deformation two glass
phases are observed. Both phases represent the anisotropic glass of the orbital
ferromagnetic vector l -- the orbital glass (OG). The phases differ by the spin
structure: the spin nematic vector d can be either in the ordered spin nematic
(SN) state or in the disordered spin-glass (SG) state. The first phase (OG-SN)
is formed under conventional cooling from normal 3He. The second phase (OG-SG)
is metastable, being obtained by cooling through the superfluid transition
temperature, when large enough resonant continuous radio-frequency excitation
are applied. NMR signature of different phases allows us to measure the
parameter of the global anisotropy of the orbital glass induced by deformation.Comment: 7 pages, 6 figures, Submitted to Pis'ma v ZhETF (JETP Letters
Nuclear Schiff moment and soft vibrational modes
The atomic electric dipole moment (EDM) currently searched by a number of
experimental groups requires that both parity and time-reversal invariance be
violated. According to current theoretical understanding, the EDM is induced by
the nuclear Schiff moment. The enhancement of the Schiff moment by the
combination of static quadrupole and octupole deformation was predicted
earlier. Here we study a further idea of the possible enhancement in the
absence of static deformation but in a nuclear system with soft collective
vibrations of two types. Both analytical approximation and numerical solution
of the simplified problem confirm the presence of the enhancement. We discuss
related aspects of nuclear structure which should be studied beyond mean-field
and random phase approximations.Comment: 14 pages, 4 figure
Nuclear Schiff moment in nuclei with soft octupole and quadrupole vibrations
Nuclear forces violating parity and time reversal invariance (-odd) produce -odd nuclear moments, for example, the
nuclear Schiff moment. In turn, this moment can induce the electric dipole
moment in the atom. The nuclear Schiff moment is predicted to be enhanced in
nuclei with static quadrupole and octupole deformation. The analogous
suggestion of the enhanced contribution to the Schiff moment from the soft
collective quadrupole and octupole vibrations in spherical nuclei is tested in
this article in the framework of the quasiparticle random phase approximation
with separable quadrupole and octupole forces applied to the odd Ra
and Rn isotopes. We confirm the existence of the enhancement effect
due to the soft modes. However, in the standard approximation the enhancement
is strongly reduced by a small weight of the corresponding "particle + phonon"
component in a complicated wave function of a soft nucleus. The perspectives of
a better description of the structure of heavy soft nuclei are discussed.Comment: 27 pages, 3 figures, minor corrections in references adde
Monitoring the wear of the refractory lining in the blast-furnace hearth
The Razgar Gorna computer program is developed for calculating two-dimensional temperature fields in any vertical and horizontal cross section of the blast-furnace hearth. In the calculations, the heat-conduction equations are solved by means of readings from many temperature sensors (up to 1000, depending on the volume) installed within the furnace lining between the refractory modules. Continuous temperature monitoring at each point permits the determination of the remaining lining thickness and prediction of the onset of lining wear, as necessary. A mathematical model is employed in continuous temperature monitoring of the lining. The database of the Razgar Gorna program relies on the collection, analysis, and transmission of information from the temperature or heat-flux sensors. The program is in use at blast furnaces in Chinese steelworks at Jinan (two furnaces), Jiyuan, and Liuzhou. © 2013 Allerton Press, Inc
- …