Correlations in self-bound systems of identical fermions

A method for the calculation of translationally invariant wave functions for systems of identical fermions with arbitrary potential of pair interaction is developed. It is based on the well-known result that the essential dynamic part of the Hamiltonian for the system of identical particles is the Reduced Hamiltonian operator describing relative movement of two particles inside the system. The eigenfunctions of this operator take into account all correlations caused by interaction. These eigenfunctions are basic for the construction of the components (i.e. the functions with a lower degree of antisymmetry) of the system wave functions. The main problem of this approach appears to be antisymmetrization of the components. The developed universal algorithm for antisymmetrization gives a possibility to perform this operation in a simple way and keep numerical approximations under control.Comment: 20 pages REVTeX, submitted to Lithuanian J. Phy

Atsiliepiant į laiko reikalavimus

1980 m. gruodžio mėnesį įvyko visuomenės mokslų dėstytojų pasitarimas-seminaras, skirtas TSKP CK spalio (1980 m.) plenumo iškeltiems uždaviniams nagrinėti bei TSKP CK projektui „Pagrindinės TSRS ekonominio ir socialinio vystymo kryptys 1981–1985 metams ir laikotarpiui iki 1990 metų“ aptarti. Apžvelgiamas LKP CK sekretoriaus L. Šepečio pranešimas apie aktualius visuomenės mokslų dėstytojų darbo klausimus. Jis kalbėjo apie visuomenės mokslų dėstymo perimamumo, studentų pažangumo, dėstytojų pedagoginio meistriškumo, jų mokslinio darbo, mokslinės kvalifikacijos kėlimo klausimus

The general harmonic-oscillator brackets: compact expression, symmetries, sums and Fortran code

We present a very simple expression and a Fortran code for the fast and precise calculation of three-dimensional harmonic-oscillator transformation brackets. The complete system of symmetries for the brackets along with analytical expressions for sums, containing products of two and three brackets, is given.Comment: 13 pages, accepted for publication in Nuclear Physics

Co valence and possible spin transformation in diluted magnetic semiconductors Zn/sub 1-z/Mg/sub z/Co/sub 0.15/O and Zn/sub 1-x/Co/sub x/O

In this paper, possible spin transformation and Co valence in dilute magnetic semiconductors is studied. Polycrystalline samples of Zn/sub 1-x/Co/sub x/O (0.05/spl les/x/spl les/0.17) and Zn/sub 1-z/Mg/sub z/Co/sub 0.15/O are prepared by rapid oxalate decomposition technique. X-ray diffraction is used to determine phase purity of the samples. Co valence state 2+ is determined by X-ray absorption near edge spectroscopy (XANES) using synchrotron irradiation. Magnetic properties measured show that all samples are paramagnetic and magnetization hysteresis measurement indicated that there is no trace of ferromagnetism. From Curie-Weiss fittings at high temperature region, the effective magnetic moment (/spl mu//sub eff/) is 3.87/spl mu//sub B//Co which corresponds to that of tetrahedral Co/sup 2+/ high spin state. When fitting at T approaches 0 K, /spl mu//sub eff/ = 2.82/spl mu//sub B//Co is observed indicating a possible spin state transition to Co/sup 2+/ low spin state

Facile electrochemical synthesis of ultrathin iron oxyhydroxide nanosheets for the oxygen evolution reaction

We propose a facile approach to synthesise ultrathin iron oxyhydroxide nanosheets for use in catalysing the electrochemical oxygen evolution reaction. This two dimensional material lowers the overpotential and provides a platform for further performance enhancement via integration of species such as nickel into an ultrathin nanosheet structure

Nepusiausvyro perdavimo testo galios aproksimavimas

In this paper we apply Poisson distribution in order to approximate the power of the Transmission Disequilibrium Test (TDT). In this research we calculated the power of the TDT for different values of sample size n and different values of allele transmission frequencies p. The research showed that Poisson approximation have smaller errors than Normal approximation when the power is between 0.8 and 0.95 and sample size m is equal or bigger than 50.Straipsnio tikslas yra pasiūlyti naują nepusiausvyro perdavimo testo (NPT) galios aproksimaciją Puasono skirstiniu. Parodoma, kad NPT aproksimacija Puasono skirstiniu yra tinkamesnė nei normaliuoju skirstiniu, kai binominio skirstinio sėkmės tikimybė p artėja į nulį, o imties dydis n artėja į begalybę. Palyginus siūlomo metodo ir kitų autorių rezultatus, gauta, kad kai galios reikšmė yra tarp 0.8 ir 0.95, o imties dydis didesnis arba lygus 50, siūlomas metodas turi mažesnes paklaidas nei normaliosios aproksimacijos modelis

Very strong intrinsic supercurrent carrying ability and vortex avalanches in (Ba,K)Fe2As2 superconducting single crystals

We report that single crystals of (Ba,K)Fe2As2 with Tc = 32 K have a pinning potential, U0, as high as 10^4 K, with U0 showing very little field depend-ence. In addition, the (Ba,K)Fe2As2 single crystals become isotropic at low temperatures and high magnetic fields, resulting in a very rigid vortex lattice, even in fields very close to Hc2. The rigid vortices in the two dimensional (Ba,K)Fe2As2 distinguish this compound from 2D high Tc cuprate superconductors with 2D vortices, and make it being capable of cearrying very high critical current.Flux jumping due to high Jc was also observed in large samples at low temperatures.Comment: 4 pages, 7 figures. submitte