arXiv subjects

T. Kuehl

Publications and source records attributed to T. Kuehl.

4 recordsLinked to original sources

arXiv2007

Microscopic Cluster Model for Exotic Nuclei

For a better understanding of the dynamics of exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. Theoretically the basic task consists in formulating an easy solvable theory able to reproduce structures and transitions of known nuclei which should be then used to calculate the sparely known properties of proton- or neutron-rich nuclei. In this paper we start by calculating energies and distributions of A\leq4 nuclei withing a unitary correlation model restricted to include only two-body correlations. The structure of complex nuclei is then calculated extending the model to include correlation effects of higher order.

nucl-th↗

arXiv2007

Correlation Effects on the Charge Radii of Exotic Nuclei

The structures and distributions of light nuclei are investigated within a microscopic correlation model. Two particle correlations are responsible for the scattering of model particles either to low momentum- or to high momentum-states. The low momentum states form the model space while the high momentum states are used to calculate the G-matrix. The three and higher order particle correlations do not play a role in the latter calculation especially if the correlations induced by the scattering operator are of sufficient short range. They modify however, via the long tail of the nuclear potential, the Slater determinant of the (A) particles by generating excited Slater's determinants.

nucl-th↗

arXiv2006

Correlations in Many Electron Systems: Theory and Applications

In this contribution we present calculations performed for interacting electron systems within a non-perturbative formulation of the cluster theory. Extrapolation of the model to describe the time dependence of the interacting systems is feasible and planed. The theory is based on the unitary operator $e^{iS}$ ({\it S} is the correlation operator) formalism which, in this paper, is treated non perturbatively within many-particle correlations. The application of the derived equations to few-body systems is realized in terms of Generalized Linearization Approximations (GLA) and via the Cluster Factorization Theory (CFT). To check the reliability of the model we present two different applications. In the first we evaluate the transitions energies in Helium-, Lithium-, Beryllium-, and Boron-like Oxygen. The calculation aims to a precise determination of the satellite transitions which play an important role in plasma diagnostics. In a second we investigate a non-perturbative method to evaluate the charge radii of the Helium and Lithium isotopes by using the Isotopic Shift theory. We have found that our model leads naturally to components of $e^--e^+$ pair in the two-electron wave functions of the Helium isotopes and three-electron wave functions of the Lithium isotopes. The possible connection of these terms to the QED leading diagrams is postulated.

physics.atom-ph↗

arXiv2002

Cluster Transformation Coefficients for Structure and Dynamics Calculations in n-Particle Systems: Atoms, Nuclei, and Quarks

The structure and dynamics of an n-particle system are described with coupled nonlinear Heisenberg's commutator equations where the nonlinear terms are generated by the two-body interaction that excites the reference vacuum via particle-particle and particle-hole excitations. Nonperturbative solutions of the system are obtained with the use of dynamic linearization approximation and cluster transformation coefficients. The dynamic linearization approximation converts the commutator chain into an eigenvalue problem. The cluster coefficients factorize the matrix elements of the (n)-particles or particle-hole systems in terms of the matrix elements of the (n-1)-systems coupled to a particle-particle, particle-hole, and hole-hole boson. Group properties of the particle-particle, particle-hole, and hole-hole permutation groups simplify the calculation of these coefficients. The particle-particle vacuum-excitations generate superconductive diagrams in the dynamics of 3-quarks systems. Applications of the model to fermionic and bosonic systems are discussed.

hep-th↗