Norm kernels and the closeness relation for Pauli-allowed basis functions

The norm kernel of the generator-coordinate method is shown to be a symmetric kernel of an integral equation with eigenfunctions defined in the Fock--Bargmann space and forming a complete set of orthonormalized states (classified with the use of SU(3) symmetry indices) satisfying the Pauli exclusion principle. This interpretation allows to develop a method which, even in the presence of the SU(3) degeneracy, provides for a consistent way to introduce additional quantum numbers for the classification of the basis states. In order to set the asymptotic boundary conditions for the expansion coefficients of a wave function in the SU(3) basis, a complementary basis of functions with partial angular momenta as good quantum numbers is needed. Norm kernels of the binary systems 6He+p, 6He+n, 6He+4He, and 8He+4He are considered in detail.Comment: 25 pages; submitted to Few-Body System

Phenomenological three-cluster model of 6^{6}He

By using the method of hyperspherical functions within the appropriate for this method K_{\min} approximation, the simple three-cluster model for description of the ground state and the continuous spectrum states of \6He is developed. It is shown that many properties of \6He (its large rms radius and large values of the matrix elements of electromagnetic transitions from the ground state into the continuous spectrum) follow from the fact that the potential energy of \6He system decreases very slowly (as \rho^{-3}) and the binding energy is small

FRACTURE ANALYSIS OF 20 Н3 STEEL SAMPLES AFTER TENSILE TESTS

Samples of 20Х3 steel after quenching and tempering under different regimes were studied. By means of macro analysis and scanning electron microscopy the features of the fracture surface relief of samples after tensile tests were studied.В работе исследованы образцы стали 20Х3 после закалки и отпуска по различным режимам. С помощью макроанализа и растровой электронной микроскопии изучены особенности рельефа поверхности разрушения образцов после растяжения

RESEARCH OF THE PRE-STRAIN AND ANNEALING EFFECT ON THE STRUCTURE AND MECHANICAL BEHAVIOR OF MEDIUM CARBON STEELS

The influence of pre-strain value of 2 % and subsequent low-temperature annealing at 250 °C on the structure and mechanical properties of medium carbon steels 37G2S and 37HGF.Изучено влияние предварительной деформации величиной 2 % и последующего низкотемпературного отжига при 250 оС на структуру и механические свойства среднеуглеродистых сталей 37Г2 С и 37ХГФ

A netron halo in 8He

The structure of $^8$He is investigated within a three-cluster microscopic model. The three-cluster configuration $\alpha+^2n+^2n$ was used to describe the properties of the ground state of the nucleus. The obtained results evidently indicate the existence of a neutron halo in $^8$He.Comment: 14 pages, 6 postscript figures, submitted to Phys. Atom. Nuc

Varying constants, Gravitation and Cosmology

Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.Comment: 145 pages, 10 figures, Review for Living Reviews in Relativit