328 research outputs found
Accurate Localization and Identification of Six Hard X-ray Sources from Chandra and XMM-Newton data
We present the results of Chandra and XMM-Newton observations for six hard
X-ray sources (IGR J12134-6015, IGR J18293-1213, IGR J18219-1347, IGR
J17350-2045, IGR J18048-1455, XTE J1901+014) from the INTEGRAL all-sky survey.
Based on these observations, we have improved significantly the localization
accuracy of the objects and, therefore, have managed to identify their optical
counterparts. Using data from the publicly available 2MASS and UKIDSS infrared
sky surveys as well as data from the SOFI/NTT telescope (European Southern
Observatory), we have determined the magnitudes of the optical counterparts,
estimated their types and (in some cases) the distances to the program objects.
A triplet of iron lines with energies of 6.4, 6.7, and 6.9 keV has been
detected in the X-ray spectrum of IGR J18048-1455; together with the detection
of pulsations with a period of ~1440 s from this source, this has allowed it to
be classified as a cataclysmic variable, most likely an intermediate polar. In
addition, broadband X-ray spectra of IGR J12134-6015 and IGR J17350-2045 in
combination with infrared and radio observations suggest an extragalactic
nature of these objects. The source IGR J18219-1347 presumably belongs to the
class of high-mass X-ray binaries.Comment: 15 pages, 9 figures. Will be published in Astronomy Letters, 2012,
Vol. 38, No. 10, pp. 629-63
Cotangent bundle quantization: Entangling of metric and magnetic field
For manifolds of noncompact type endowed with an affine connection
(for example, the Levi-Civita connection) and a closed 2-form (magnetic field)
we define a Hilbert algebra structure in the space and
construct an irreducible representation of this algebra in . This
algebra is automatically extended to polynomial in momenta functions and
distributions. Under some natural conditions this algebra is unique. The
non-commutative product over is given by an explicit integral
formula. This product is exact (not formal) and is expressed in invariant
geometrical terms. Our analysis reveals this product has a front, which is
described in terms of geodesic triangles in . The quantization of
-functions induces a family of symplectic reflections in
and generates a magneto-geodesic connection on . This
symplectic connection entangles, on the phase space level, the original affine
structure on and the magnetic field. In the classical approximation,
the -part of the quantum product contains the Ricci curvature of
and a magneto-geodesic coupling tensor.Comment: Latex, 38 pages, 5 figures, minor correction
Graphene as a quantum surface with curvature-strain preserving dynamics
We discuss how the curvature and the strain density of the atomic lattice
generate the quantization of graphene sheets as well as the dynamics of
geometric quasiparticles propagating along the constant curvature/strain
levels. The internal kinetic momentum of Riemannian oriented surface (a vector
field preserving the Gaussian curvature and the area) is determined.Comment: 13p, minor correction
Tverberg-type theorems for intersecting by rays
In this paper we consider some results on intersection between rays and a
given family of convex, compact sets. These results are similar to the center
point theorem, and Tverberg's theorem on partitions of a point set
Quantum Magnetic Algebra and Magnetic Curvature
The symplectic geometry of the phase space associated with a charged particle
is determined by the addition of the Faraday 2-form to the standard structure
on the Euclidean phase space. In this paper we describe the corresponding
algebra of Weyl-symmetrized functions in coordinate and momentum operators
satisfying nonlinear commutation relations. The multiplication in this algebra
generates an associative product of functions on the phase space. This product
is given by an integral kernel whose phase is the symplectic area of a
groupoid-consistent membrane. A symplectic phase space connection with
non-trivial curvature is extracted from the magnetic reflections associated
with the Stratonovich quantizer. Zero and constant curvature cases are
considered as examples. The quantization with both static and time dependent
electromagnetic fields is obtained. The expansion of the product by the
deformation parameter, written in the covariant form, is compared with the
known deformation quantization formulas.Comment: 23 page
ANALIZA STANJA NAPREZANJA OBLOGE OKNA NA KONTAKTNOJ ZONI ANHIDRITA I KAMENE SOLI
The main question of this paper is the stress-strain state prediction of the vertical shaft’s combined lining located at the interface of two layers of dolomite and salt. The study predicts geomechanical processes at the contact of the dolomite layer and the salt layer in the vicinity of the vertical shaft’s expanded section, taking into account the operating life of a vertical shaft is equal to 50 years. The results combined lining’s stress-strain state, represented as a four – layer medium, where the external layer is concrete, and the three inner layers are used to account for the heterogeneity of cast-iron tubing and are compared with the results received when taking into account the pipe structure. The solution of the problem was carried out in a three-dimensional statement. The calculation of the tubing lining, considering its actual geometry, will increase the accuracy of the forecast of the stress state of the lining, which in turn will favourably affect the justification of its parameters.Glavna problematika ovoga rada očituje se u predviđanju stanja naprezanja – deformacije kombinirane obloge vertikalnoga okna smještene na kontaktu dvaju slojeva dolomita i soli. Studija predviđa geomehaničke procese na kontaktu dolomitnoga sloja i sloja soli u blizini proširenoga presjeka vertikalnoga okna, uzimajući u obzir radni vijek okna od 50 godina. Rezultati stanja naprezanja – deformacija kombinirane četveroslojne obloge, gdje je vanjski sloj beton, a tri unutarnja sloja od lijevanoga željeza, uzimajući u obzir heterogenost, uspoređeni su s rezultatima dobivenim kada je u obzir uzeta isključivo struktura cijevi. Rješenje problema provedeno je u trodimenzionalnome sustavu. Proračun obloge cijevi, uzimajući u obzir stvarnu geometriju, povećat će točnost predviđanja stanja naprezanja obloge, što upućuje na važnost parametara obloge
Weyl's symbols of Heisenberg operators of canonical coordinates and momenta as quantum characteristics
The knowledge of quantum phase flow induced under the Weyl's association rule
by the evolution of Heisenberg operators of canonical coordinates and momenta
allows to find the evolution of symbols of generic Heisenberg operators. The
quantum phase flow curves obey the quantum Hamilton's equations and play the
role of characteristics. At any fixed level of accuracy of semiclassical
expansion, quantum characteristics can be constructed by solving a coupled
system of first-order ordinary differential equations for quantum trajectories
and generalized Jacobi fields. Classical and quantum constraint systems are
discussed. The phase-space analytic geometry based on the star-product
operation can hardly be visualized. The statement "quantum trajectory belongs
to a constraint submanifold" can be changed e.g. to the opposite by a unitary
transformation. Some of relations among quantum objects in phase space are,
however, left invariant by unitary transformations and support partly geometric
relations of belonging and intersection. Quantum phase flow satisfies the
star-composition law and preserves hamiltonian and constraint star-functions.Comment: 27 pages REVTeX, 6 EPS Figures. New references added. Accepted for
publication to JM
Measurement of qutrits
We proposed the procedure of measuring the unknown state of the three-level
system - the qutrit, which was realized as the arbitrary polarization state of
the single-mode biphoton field. This procedure is accomplished for the set of
the pure states of qutrits; this set is defined by the properties of SU(2)
transformations, that are done by the polarization transformers.Comment: 9 pages, 9 figure
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