Bound states of anti-nucleons in finite nuclei

We study the bound states of anti-nucleons emerging from the lower continuum in finite nuclei within the relativistic Hartree approach including the contributions of the Dirac sea to the source terms of the meson fields. The Dirac equation is reduced to two Schr\"{o}dinger-equivalent equations for the nucleon and the anti-nucleon respectively. These two equations are solved simultaneously in an iteration procedure. Numerical results show that the bound levels of anti-nucleons vary drastically when the vacuum contributions are taken into account.Comment: 8 pages, no figures. Proceedings of International Conference on Nonequilibrium and Nonlinear Dynamics in Nuclear and Other Finite Systems, Beijing, China 2001; AIP conference proceedings 597, edited by Zhuxia Li, Ke Wu, Xizhen Wu, Enguang Zhao, and F. Sakata (Melville, New York, 2001) page 112-11

How to Defeat W\"{u}thrich’s Abysmal Embarrassment Argument against Space-Time Structuralism

In his 2009 PSA Recent Ph.D. Award winning contribution to the bi-annual PSA Conference at Pittsburgh in 2008, C. Wu ̈thrich mounted an argument against struc- turalism about space-time in the context of the General Theory of Relativity (GTR), to the effect that structuralists cannot discern space-time points. An “abysmal embarrass- ment” for the structuralist, Wu ̈thrich judged. Wu ̈thrich’s characterisation of space-time structuralism is however incorrect. We demonstrate how, on the basis of a correct char- acterisation of space-time structuralism, it is possible to discern space-time points in the GTR-structures under consideration. Thus Wu ̈thrich’s argument crumbles

ON NEWTON-RAPHSON METHOD

Recent versions of the well-known Newton-Raphson method for solving algebraic equations are presented. First of these is the method given by J. H. He in 2003. He reduces the problem to solving a second degree polynomial equation. However He’s method is not applicable when this equation has complex roots. In 2008, D. Wei, J. Wu and M. Mei eliminated this deficiency, obtaining a third order polynomial equation, which has always a real root. First of the authors of present paper obtained higher order polynomial equations, which for orders 2 and 3 are reduced to equations given by He and respectively by Wei-Wu-Mei, with much improved form. In this paper, we present these methods. An example is given.newton-raphson

Non-minimal Wu-Yang wormhole

We discuss exact solutions of three-parameter non-minimal Einstein-Yang-Mills model, which describe the wormholes of a new type. These wormholes are considered to be supported by SU(2)-symmetric Yang-Mills field, non-minimally coupled to gravity, the Wu-Yang ansatz for the gauge field being used. We distinguish between regular solutions, describing traversable non-minimal Wu-Yang wormholes, and black wormholes possessing one or two event horizons. The relation between the asymptotic mass of the regular traversable Wu-Yang wormhole and its throat radius is analysed.Comment: 9 pages, 2 figures, typos corrected, 2 references adde

On the electronic structure of CaCuO2 and SrCuO2

Recent electronic structure calculations for the prototypical lowdimensional cuprate compounds CaCuO2 ans SrCuO2 performed by Wu et. al. (J. Phys.: Condens. Matter v. 11 p.4637 (1999))are critically reconsidered, applying high precision full-potential bandstructure methods. It is shown that the bandstructure calculations presented by the authors contain several important inconsistencies, which make their main conclusions highly questionable.Comment: 4 pages, 3 figures, submitted to J. Phys. Condens. Matte