Comparison of techniques for computing shell-model effective operators
نویسندگان
چکیده
Different techniques for calculating effective operators within the framework of the shell model using the same effective interaction and the same excitation spaces are presented. Starting with the large-basis no-core approach, we compare the time-honored perturbation-expansion approach and a modelspace truncation approach. Results for the electric quadrupole and magnetic dipole operators are presented for 6Li. The convergence trends and dependence of the effective operators on differing excitation spaces and Pauli Qoperators is studied. In addition, the dependence of the electric-quadrupole effective charge on the harmonic-oscillator frequency and the mass number, for A = 5, 6, is investigated in the model-space truncation approach.
منابع مشابه
A COMPARATIVE STUDY OF TRADITIONAL AND INTELLIGENCE SOFT COMPUTING METHODS FOR PREDICTING COMPRESSIVE STRENGTH OF SELF – COMPACTING CONCRETES
This study investigates the prediction model of compressive strength of self–compacting concrete (SCC) by utilizing soft computing techniques. The techniques consist of adaptive neuro–based fuzzy inference system (ANFIS), artificial neural network (ANN) and the hybrid of particle swarm optimization with passive congregation (PSOPC) and ANFIS called PSOPC–ANFIS. Their perf...
متن کاملuc l - th / 9 90 20 14 v 1 5 F eb 1 99 9 Shell - Model Effective Operators for Muon Capture in 20
It has been proposed that the discrepancy between the partially-conserved axialcurrent prediction and the nuclear shell-model calculations of the ratio CP/CA in the muon-capture reactions can be solved in the case of Si by introducing effective transition operators. Recently there has been experimental interest in measuring the needed angular correlations also in Ne. Inspired by this, we have p...
متن کاملApplication of non-linear regression and soft computing techniques for modeling process of pollutant adsorption from industrial wastewaters
The process of pollutant adsorption from industrial wastewaters is a multivariate problem. This process is affected by many factors including the contact time (T), pH, adsorbent weight (m), and solution concentration (ppm). The main target of this work is to model and evaluate the process of pollutant adsorption from industrial wastewaters using the non-linear multivariate regression and intell...
متن کاملMicroscopic origins of effective charges in the shell model
We use a large-scale 6h̄Ω calculation for 6Li with microscopically derived twobody interaction to construct the 0h̄Ω 0p-shell effective hamiltonian, electric quadrupole, and magnetic dipole operators. While the E2 and M1 6h̄Ω operators are one-body operators with free nucleon charges, the effective operators are two-body operators with substantially different renormalization for the isoscalar and ...
متن کاملElectromagnetic Transitions with Effective Operators
In the no-core shell model formalism we compute effective oneand two-body operators, using the Lee-Suzuki procedure within the two-body cluster approximation. We evaluate the validity of the latter through calculations in reduced model spaces. In particular, we test the results for the two-body system and find that indeed the effective operators in the reduced space reproduce the expectation va...
متن کامل