Thomas Weber

Realistic nuclear Hamiltonian: Ab exitu approach

Fully-microscopic No-core Shell Model (NCSM) calculations of all stable s and p shell nuclei are used to determine realistic NN interaction JISP16 describing not only the two-nucleon data but the binding energies and spectra of nuclei with A {le} 16 as well. The JISP16 interaction, providing rapid convergence of the NCSM calculations, is obtained in an ab exitu approach by phase-equivalent transformations of the JISP6 NN interaction.

Novel NN interaction and the spectroscopy of light nuclei

Abstract Nucleon–nucleon ( NN ) phase shifts and the spectroscopy of A ⩽ 6 nuclei are successfully described by an inverse scattering potential that is separable with oscillator form factors.

Elementary Considerations of the Time and Geometry of Rotating Reference Frames

Elementary methods of synchronization on rotating systems are discussed. It is argued that the continuous time synchronization preferred by Klauber and others is not the time synchronization for making distance measurements but rather leads to a velocity of light which depends on direction. A paradox discovered by Selleri will also be discussed. This paradox involves a limiting case of the rotating disk in which the edge of the disk approximates an inertial frame where the velocity of light depends on direction. In addition, a paradox on the conservation of charge will be resolved by referring to the geometry of the rotating disk. Finally, the isotropy of the velocity of light on rotating frames is discussed along with the experimental evidence of Brillet and Hall.

GSI resonances are not von Neumann-Wigner states

Abstract It has been suggested that the sharp resonances observed at GSI may be due to bound states of the e + e − system. Two research groups working independently have supported this suggestion by numerical calculations based on several non-local relativistic two-body equations derived from QED. Both groups have drawn an analogy between the continuum bound states found in their numerical calculations and those found by von Neumann and Wigner in the context ov non-relativistic quantum mechanics. Abruzov et al. [JETP Lett. 50 (1989) 262] derived a certain quasi-local non-relativistic potential as an approximation to the relativistic equation used im their numerical work, and susggested without proof that this non-relativistic potential could support continuum bound states of the von Neumann-Wigner Kind. We show that this conjucture conflict wwith a theorem due to Weidmann and Simon.

P24 Plasma Physics Summer School 2012 Los Alamos National Laboratory Summer lecture series for students

This report covers the 2012 LANL summer lecture series for students. The lectures were: (1) Tom Intrator, P24 LANL: Kick off, Introduction - What is a plasma; (2) Bruno Bauer, Univ. Nevada-Reno: Derivation of plasma fluid equations; (3) Juan Fernandez, P24 LANL Overview of research being done in p-24; (4) Tom Intrator, P24 LANL: Intro to dynamo, reconnection, shocks; (5) Bill Daughton X-CP6 LANL: Intro to computational particle in cell methods; (6) Kirk Flippo, P24 LANL: High energy density plasmas; (7) Thom Weber, P24 LANL: Energy crisis, fission, fusion, non carbon fuel cycles; (8) Tom Awe, Sandia National Laboratory: Magneto Inertial Fusion; and (9) Yongho Kim, P24 LANL: Industrial technologies.

Spectroscopy of light nuclei with realistic NN interaction JISP

Recent results of our systematic ab initio studies of the spectroscopy of s- and p-shell nuclei in fully microscopic large-scale (up to a few hundred million basis functions) no-core shell-model calculations are presented. A new high-quality realistic nonlocal NN interaction JISP is used. This interaction is obtained in the J-matrix inverse-scattering approach (JISP stands for the J-matrix inverse-scattering potential) and is of the form of a small-rank matrix in the oscillator basis in each of the NN partial waves, providing a very fast convergence in shell-model studies. The current purely two-body JISP model of the nucleon-nucleon interaction JISP16 provides not only an excellent description of two-nucleon data (deuteron properties and np scattering) with χ2/datum = 1.05 but also a better description of a wide range of observables (binding energies, spectra, rms radii, quadrupole moments, electromagnetic-transition probabilities, etc.) in all s-and p-shell nuclei than the best modern interaction models combining realistic nucleon-nucleon and three-nucleon interactions.

Charge-dependent NN interaction in the J-matrix inverse scattering approach

A method for constructing interaction within the J-matrix inverse scattering approach in the case of charged particles is proposed. A charge-dependent nonlocal nucleon-nucleon interaction (CD JISP) has been constructed, which is a generalization of the JISP16 interaction. Interaction in pp, nn, and np partial waves is presented by small matrices in the oscillator basis with ħω = 40 MeV; therefore, it can be directly used in many-body calculations within the shell model and in the resonating group model. The CD JISP interaction reproduces the np-and pp-scattering data and deuteron observables with high accuracy.

Nonlocal nucleon-nucleon interaction JISP

The J-matrix inverse scattering formalism is described and a new type of nucleon-nucleon interaction JISP is constructed within its framework. Interaction for each partial NN scattering is represented by a small matrix in the oscillator basis, which allows its direct use in multiparticle shell-model calculations and in calculations within the resonating group approximation. The JISP reproduces np scattering data and deuteron characteristics with an accuracy of modern realistic NN potentials (x2/datum = 1.05). The generalization of this interaction which takes into account violation of charge independence of nucleon-nucleon forces is proposed and pp scattering phases calculated with this new charge-dependent interaction CD-JISP are discussed.

Nonlocal inverse-scattering nucleon-nucleon interaction and spectra of s-and p-shell nuclei

Nucleon-nucleon interaction is constructed in the J-matrix inverse scattering approach developed by us. The interaction has the form of a matrix in the oscillator basis in each partial wave. The rank of the matrix is not large though the description of the NN scattering data is comparable in quality with that provided by the best modern NN interaction potentials (x2/datum = 1.03). Various phase-equivalent transformations (PETs) that do not affect the description of the scattering data are then used. They allow, in particular, all experimentally known deuteron characteristics to be reproduced with this interaction. The interaction is used in calculations of properties of light nuclei (to A = 16) by the no-core shell model (NCSM), where all nucleons are spectroscopically active. In the NCSM calculations the ultimate fit of the interaction is performed: using PETs, we make it capable of describing binding energies and spectra of all nuclei in question. Note that three-nucleon forces are not used in our approach.