195 research outputs found
Deuteron-equivalent and phase-equivalent interactions within light nuclei
Background: Phase-equivalent transformations (PETs) are well-known in quantum
scattering and inverse scattering theory. PETs do not affect scattering phase
shifts and bound state energies of two-body system but are conventionally
supposed to modify two-body bound state observables such as the rms radius and
electromagnetic moments. Purpose: In order to preserve all bound state
observables, we propose a new particular case of PETs, a deuteron-equivalent
transformation (DET-PET), which leaves unchanged not only scattering phase
shifts and bound state (deuteron) binding energy but also the bound state wave
function. Methods: The construction of DET-PET is discussed; equations defining
the simplest DET-PETs are derived. We apply these simplest DET-PETs to the
JISP16 interaction and use the transformed interactions in
calculations of H and He binding energies in the No-core Full
Configuration (NCFC) approach based on extrapolations of the No-core Shell
Model (NCSM) basis space results to the infinite basis space. Results: We
demonstrate the DET-PET modification of the scattering wave functions and
study the DET-PET manifestation in the binding energies of H and He
nuclei and their correlation (Tjon line). Conclusions: It is shown that some
DET-PETs generate modifications of the central component while the others
modify the tensor component of the interaction. DET-PETs are able to
modify significantly the scattering wave functions and hence the off-shell
properties of the interaction. DET-PETs give rise to significant changes
in the binding energies of H (in the range of approximately 1.5 MeV) and
He (in the range of more than 9 MeV) and are able to modify the correlation
patterns of binding energies of these nuclei
Nucleon-nucleon interaction in the -matrix inverse scattering approach and few-nucleon systems
The nucleon-nucleon interaction is constructed by means of the -matrix
version of inverse scattering theory. Ambiguities of the interaction are
eliminated by postulating tridiagonal and quasi-tridiagonal forms of the
potential matrix in the oscillator basis in uncoupled and coupled waves,
respectively. The obtained interaction is very accurate in reproducing the
scattering data and deuteron properties. The interaction is used in the no-core
shell model calculations of H and He nuclei. The resulting binding
energies of H and He are very close to experimental values.Comment: Text is revised, new figures and references adde
NN potentials from inverse scattering in the J-matrix approach
An approximate inverse scattering method [7,8] has been used to construct
separable potentials with the Laguerre form factors. As an application, we
invert the phase shifts of proton-proton in the and
channels and neutron-proton in the channel elastic scattering. In
the latter case the deuteron wave function of a realistic potential was
used as input.Comment: LaTex2e, 17 pages, 3 Postscript figures; corrected typo
Inverse scattering J-matrix approach to nucleon-nucleus scattering and the shell model
The -matrix inverse scattering approach can be used as an alternative to a
conventional -matrix in analyzing scattering phase shifts and extracting
resonance energies and widths from experimental data. A great advantage of the
-matrix is that it provides eigenstates directly related to the ones
obtained in the shell model in a given model space and with a given value of
the oscillator spacing . This relationship is of a particular
interest in the cases when a many-body system does not have a resonant state or
the resonance is broad and its energy can differ significantly from the shell
model eigenstate. We discuss the -matrix inverse scattering technique,
extend it for the case of charged colliding particles and apply it to the
analysis of and scattering. The results are compared with
the No-core Shell Model calculations of He and Li.Comment: Some text is added following suggestions of a journal refere
Multi-channel phase-equivalent transformation and supersymmetry
Phase-equivalent transformation of local interaction is generalized to the
multi-channel case. Generally, the transformation does not change the number of
the bound states in the system and their energies. However, with a special
choice of the parameters, the transformation removes one of the bound states
and is equivalent to the multi-channel supersymmetry transformation recently
suggested by Sparenberg and Baye. Using the transformation, it is also possible
to add a bound state to the discrete spectrum of the system at a given energy
if the angular momentum at least in one of the coupled channels .Comment: 9 pages, revtex; to be published in Phys. At. Nucl. (Oct. 2000
Formal and model driven design of the bright light therapy system Luxamet
Seasonal depression seriously diminishes the quality of life for many patients. To improve their condition, we propose LUXAMET, a bright light therapy system. This system has the potential to relieve patients from some of the symptoms caused by seasonal depression. The system was designed with a formal and model driven design methodology. This methodology enabled us to minimize systemic hazards, like blinding patients with an unhealthy dose of light. This was achieved by controlling race conditions and memory leaks, during design time. We prove that the system specification is deadlock as well as livelock free and there are no invariant violations. These proofs, together with the similarity between specification model and implementation code, make us confident that the implemented system is a reliable tool which can help patients during seasonal depression
--Dependence of Bond Energies in Double--- Hypernuclei
The -dependence of the bond energy of the
hypernuclear ground states is calculated in a three-body
model and in the Skyrme-Hartree-Fock approach.
Various and -nucleus or potentials
are used and the sensitivity of to the interactions
is discussed. It is shown that in medium and heavy
hypernuclei, is a linear function of
, where is rms radius of the hyperon orbital. It
looks unlikely that it will be possible to extract
interaction from the double- hypernuclear energies only, the
additional information about the -core interaction, in particular, on
is needed.Comment: 11 pages, LaTex, 3 figure
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