Quantum discord in spin-cluster materials

The total quantum correlation (discord) in Heisenberg dimers is expressed via the spin-spin correlation function, internal energy, specific heat or magnetic susceptibility. This allows one to indirectly measure the discord through neutron scattering, as well as calorimetric or magnetometric experiments. Using the available experimental data, we found the discord for a number of binuclear Heisenberg substances with both antiferro- and ferromagnetic interactions. For the dimerized antiferromagnet copper nitrate Cu(NO_3)_2*2.5H_2O, the three independent experimental methods named above lead to a discord of approximately 0.2-0.3 bit/dimer at a temperature of 4 K. We also determined the temperature behavior of discord for hydrated and anhydrous copper acetates, as well as for the ferromagnetic binuclear copper acetate complex [Cu_2L(OAc)]*6H_2O, where L is a ligand.Comment: 7 pages, 6 figure

A Lithium Experiment in the Program of Solar Neutrino Research

The experiments sensitive to pp-neutrinos from the Sun are very perspective for the precise measurement of a mixing angle $\theta_{12}$. A $\nu$e$^{-}$ scattering experiment (Xmass) and/or a charged-current experiment (the indium detector) can measure the flux of electron pp-neutrinos. One can find the total flux of pp-neutrinos from a luminosity constraint after the contribution of $^7$Be and CNO neutrinos to the total luminosity of the Sun are measured. The radiochemical experiment utilizing a lithium target has the high sensitivity to the CNO neutrinos, thus, it has a good promise for the precise measurement of a mixing angle and for the test of a current theory of the evolution of the stars.Comment: 6 pages, 2 figures, 1 table, A report made by A.Kopylov at International Conference NANP-2005, June 2005, Dubna, Russi

Hanbury Brown-Twiss interferometry and second-order correlations of inflaton quanta

The quantum theory of optical coherence is applied to the scrutiny of the statistical properties of the relic inflaton quanta. After adapting the description of the quantized scalar and tensor modes of the geometry to the analysis of intensity correlations, the normalized degrees of first-order and second-order coherence are computed in the concordance paradigm and are shown to encode faithfully the statistical properties of the initial quantum state. The strongly bunched curvature phonons are not only super-Poissonian but also super-chaotic. Testable inequalities are derived in the limit of large angular scales and can be physically interpreted in the light of the tenets of Hanbury Brown-Twiss interferometry. The quantum mechanical results are compared and contrasted with different situations including the one where intensity correlations are the result of a classical stochastic process. The survival of second-order correlations (not necessarily related to the purity of the initial quantum state) is addressed by defining a generalized ensemble where super-Poissonian statistics is an intrinsic property of the density matrix and turns out to be associated with finite volume effects which are expected to vanish in the thermodynamic limit.Comment: 42 pages, 3 included figures; corrected typos; to appear in Physical Review

Anomalously strong pinning of the filling factor nu=2 in epitaxial graphene

We explore the robust quantization of the Hall resistance in epitaxial graphene grown on Si-terminated SiC. Uniquely to this system, the dominance of quantum over classical capacitance in the charge transfer between the substrate and graphene is such that Landau levels (in particular, the one at exactly zero energy) remain completely filled over an extraordinarily broad range of magnetic fields. One important implication of this pinning of the filling factor is that the system can sustain a very high nondissipative current. This makes epitaxial graphene ideally suited for quantum resistance metrology, and we have achieved a precision of 3 parts in 10^10 in the Hall resistance quantization measurements

Fabrication of YAG:RE (RE = Yb, Nd, Cr) Ceramics Using Divalent Sintering Aids

High-quality YAG:RE (Yb, Nd, Cr) ceramics with CaO and MgO as sintering aids were manufactured by solid state reactive sintering method in vacuum. Influence of annealing temperature on optical properties was studied. This combination of sintering aids requires annealing temperatures at least 1300∘C to fully eliminate oxygen vacancies and at least 1400∘C to convert Cr3+ to Cr4+. It was found that annealing in oxidizing atmosphere creates strong changes in short wavelength transmittance.     Keywords: laser ceramics, Yttrium aluminium garnet, sintering aid

Problems of High-quality Doped Y2O3-ceramics Fabrication

Tm:Y2O3 , Ho:Y2O3 and Yb:Y2O3 ceramic samples were fabricated using different heat treatments modes. La2O3 (0.5 mol.%) and ZrO2 (1.5 mol.%) were used as sintering additives. Based on the investigation of structural properties of obtained samples, annealing mode was adjusted, and another set of samples with better optical quality was fabricated. In-line transmittance of the latter samples is 70% at 400nm and 75.6% at 600nm.     Keywords: Y2O3 , laser ceramic

RC J1148+0455 identification: gravitational lens or group of galaxies ?

The structure of the radio source RC B1146+052 of the ``Cold'' catalogue is investigated by data of the MIT-GB-VLA survey at 4850 MHz. This source belongs to the steep spectrum radio sources subsample of the RC catalogue. Its spectral index is $\alpha$ = -1.04. The optical image of this source obtained with 6m telescope is analysed. The radio source center is situated in a group of 8 galaxies of about 24$^m$ in the R-filter. The possible explanations of the complex structure of radio components are considered.Comment: 6 pages, 5 figures, uses psfig.sty. This was the poster as presented on Gamow Memorial Internat. Conference GMIC'99 "Early Universe: Cosmological Problems and Instrumental Technologies" in St.Petersburg, 23-27 Aug., 1999. Submitted to Proceedings to be published in A&A Transaction

Theory of plastic vortex creep

We develop a theory for plastic flux creep in a topologically disordered vortex solid phase in type-II superconductors. We propose a detailed description of the plastic vortex creep of the dislocated, amorphous vortex glass in terms of motion of dislocations driven by a transport current $j$. The {\em plastic barriers} $U_{pl}(j)\propto j^{-\mu}$ show power-law divergence at small drives with exponents $\mu=1$ for single dislocation creep and $\mu = 2/5$ for creep of dislocation bundles. The suppression of the creep rate is a hallmark of the transition from the topologically ordered vortex lattice to an amorphous vortex glass, reflecting a jump in $\mu$ from $\mu = 2/11$, characterizing creep in the topologically ordered vortex lattice near the transition, to its plastic values. The lower creep rates explain the observed increase in apparent critical currents in the dislocated vortex glass.Comment: 4 pages, 1 figur

Some aspects of examination of children with combined spine and pelvis pathology living in an industrial city

The aim of the study was to analyze the peculiarities of combined spinal and pelvic pathology in children living on the industrial area of the Irkutsk Region. To perform the analysis we carried out the clinical-roentgenological research, and when making orthopedic examination we took into consideration ecological factors and used the chart of multivariative analysis. It was found that in the structure of combined pathology, pelvis asymmetry ranks first, scoliosis ranks second, Legg - Calve - Perthes disease ranks third. According to the assessment of age structure of combined pathology we can conclude that at the equal manifestations of scoliosis, Spina bifida, retrospondylolisthesis, pelvis asymmetry, children of 11-15 y.o. more often have Legg - Calve - Perthes disease, children of 16-21 y.o. - coxarthrosis. In its turn relative share of Legg - Calve - Perthes disease cases in children living within a radius of 5 km from the industrial center is the largest (21 из 28 cases). It's important to mention that Legg - Calve - Perthes disease was registered in all examined boys and only in 35.5 % of girls. I and II degrees of manifestation of clinicoroentgenologic disorders of combined spine and pelvis pathology prevail (77 and 43 cases correspondingly) over the disorders of the III degree (15 cases)

CONCOMITANT DEFORMITIES AND DISORDERS OF THE SPINE AND PELVIS IN TERMS OF AGE ASPECT (LITERATURE REVIEW)

The article presents review of literature data concerning modern vision of concomitant deformities and disorders of the spine and pelvis in terms of age aspect, covering the causes of development of locomotor system functional disorders in children and teenagers and considering information on concomitant orthopedic pathology. The authors analyse new approaches to health evaluation in various age groups of population. The conclusion has been made, that despite certain success obtained in studying separate degenerative-dystrophic disorders of locomotor system, there is no unique solution to the problem of concomitant deformities and disorders of the spine and pelvis and their mutual interaction