Surface delta interaction in the g7/2−d5/2 model space

2016 ◽  
Vol 949 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaofei Yu ◽  
Larry Zamick
2021 ◽  
Vol 19 (5) ◽  
pp. 61-67
Author(s):  
Ali Khalaf Hasan ◽  
Dalal Naji Hameed

In the construction of this kind of shell model, we take the residual interaction to be modified surface delta interaction MSDI. We have studied the excitation energies of the 50Ca a nucleus, which contain two neutrons outside closed shell of the 48Ca. Neutrons are in the model space pfpg. The energy levels and angular momentum of all possible cases were investigated. Thereby, we have effectively utilized a theoretical process to find link among the traditional coupling angle and energy levels at different orbital within neutron - neutron interaction. We observe the energy stages appear to follow two overall functions which depend on the classical coupling angles but are unconstrained of angular momentum I. We find out that our results agree with the experimental data.


1978 ◽  
Vol 56 (6) ◽  
pp. 793-800 ◽  
Author(s):  
T. Taylor ◽  
R. G. Summers-Gill

Binding energies, excitation energies, and single nucleon transfer spectroscopic factors of the 55 ≤ A ≤ 60 cobalt isotopes have been calculated in a 1f–2p shell configuration space assuming a 56Ni core. Single-particle energies were determined empirically and two-body matrix elements were computed with the modified surface delta interaction (MSDI). The observed properties of the low-lying states are reasonably well reproduced but some low-spin states observed above 1.3 MeV are outside the model space. The theory predicts quasi-rotational bands of high-spin states in both odd- and even-A cobalt isotopes.


Author(s):  
Daniel Blatter ◽  
Anandaroop Ray ◽  
Kerry Key

Summary Bayesian inversion of electromagnetic data produces crucial uncertainty information on inferred subsurface resistivity. Due to their high computational cost, however, Bayesian inverse methods have largely been restricted to computationally expedient 1D resistivity models. In this study, we successfully demonstrate, for the first time, a fully 2D, trans-dimensional Bayesian inversion of magnetotelluric data. We render this problem tractable from a computational standpoint by using a stochastic interpolation algorithm known as a Gaussian process to achieve a parsimonious parametrization of the model vis-a-vis the dense parameter grids used in numerical forward modeling codes. The Gaussian process links a trans-dimensional, parallel tempered Markov chain Monte Carlo sampler, which explores the parsimonious model space, to MARE2DEM, an adaptive finite element forward solver. MARE2DEM computes the model response using a dense parameter mesh with resistivity assigned via the Gaussian process model. We demonstrate the new trans-dimensional Gaussian process sampler by inverting both synthetic and field magnetotelluric data for 2D models of electrical resistivity, with the field data example converging within 10 days on 148 cores, a non-negligible but tractable computational cost. For a field data inversion, our algorithm achieves a parameter reduction of over 32x compared to the fixed parameter grid used for the MARE2DEM regularized inversion. Resistivity probability distributions computed from the ensemble of models produced by the inversion yield credible intervals and interquartile plots that quantitatively show the non-linear 2D uncertainty in model structure. This uncertainty could then be propagated to other physical properties that impact resistivity including bulk composition, porosity and pore-fluid content.


Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. R767-R781 ◽  
Author(s):  
Mattia Aleardi ◽  
Silvio Pierini ◽  
Angelo Sajeva

We have compared the performances of six recently developed global optimization algorithms: imperialist competitive algorithm, firefly algorithm (FA), water cycle algorithm (WCA), whale optimization algorithm (WOA), fireworks algorithm (FWA), and quantum particle swarm optimization (QPSO). These methods have been introduced in the past few years and have found very limited or no applications to geophysical exploration problems thus far. We benchmark the algorithms’ results against the particle swarm optimization (PSO), which is a popular and well-established global search method. In particular, we are interested in assessing the exploration and exploitation capabilities of each method as the dimension of the model space increases. First, we test the different algorithms on two multiminima and two convex analytic objective functions. Then, we compare them using the residual statics corrections and 1D elastic full-waveform inversion, which are highly nonlinear geophysical optimization problems. Our results demonstrate that FA, FWA, and WOA are characterized by optimal exploration capabilities because they outperform the other approaches in the case of optimization problems with multiminima objective functions. Differently, QPSO and PSO have good exploitation capabilities because they easily solve ill-conditioned optimizations characterized by a nearly flat valley in the objective function. QPSO, PSO, and WCA offer a good compromise between exploitation and exploration.


2014 ◽  
Vol 172 (2) ◽  
pp. 389-413 ◽  
Author(s):  
Juan Zhao ◽  
Laurent Moretti ◽  
Anne Mangeney ◽  
Eléonore Stutzmann ◽  
Hiroo Kanamori ◽  
...  

Geophysics ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. A17-A21 ◽  
Author(s):  
Juan I. Sabbione ◽  
Mauricio D. Sacchi

The coefficients that synthesize seismic data via the hyperbolic Radon transform (HRT) are estimated by solving a linear-inverse problem. In the classical HRT, the computational cost of the inverse problem is proportional to the size of the data and the number of Radon coefficients. We have developed a strategy that significantly speeds up the implementation of time-domain HRTs. For this purpose, we have defined a restricted model space of coefficients applying hard thresholding to an initial low-resolution Radon gather. Then, an iterative solver that operated on the restricted model space was used to estimate the group of coefficients that synthesized the data. The method is illustrated with synthetic data and tested with a marine data example.


Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM107-SM114 ◽  
Author(s):  
James C. White ◽  
Richard W. Hobbs

The computationally efficient phase-screen forward modeling technique is extended to allow investigation of nonnormal raypaths. The code is developed to accommodate all diffracted and converted phases up to critical angle, building on a geometric construction method. The new approach relies upon prescanning the model space to assess the complexity of each screen. The propagating wavefields are then divided as a function of horizontal wavenumber, and each subset is transformed to the spatial domain separately, carrying with it angular information. This allows both locally accurate 3D phase corrections and Zoeppritz reflection and transmission coefficients to be applied. The phase-screen code is further developed to handle simple anisotropic media. During phase-screen modeling, propagation is undertaken in the wavenumber domain where exact expressions for anisotropic phase velocities are available. Traveltimes and amplitude effects from a range of anisotropic shales are computed and compared with previous published results.


2016 ◽  
Vol 94 (12) ◽  
pp. 1310-1313 ◽  
Author(s):  
Safa Bouazza

Until now experimental hyperfine structure (hfs) data of 12 even-parity Zr II levels were given in the literature. Recently new hyperfine splitting measurements of 11 other Zr II levels, of the same parity are achieved, applying fast-ion-beam laser-fluorescence spectroscopy. The hfs of these 23 gathered levels has been analysed by simultaneous parametrisation of the one- and two-body interactions, first in model space (4d + 5s)3 and secondly in extended space. For the three lowest configurations, radial parameters of the magnetic dipole A and quadrupole electric B factors are deduced in their entirety for 91Zr II, compared and discussed with calculated values, available in the literature, and also with ours, computed by means of the ab initio method. For instance we give the main experimental values of the extracted single-electron hfs parameters of 4d25s: [Formula: see text] = –2701 MHz, [Formula: see text] = –122.4 MHz, and [Formula: see text] = –113.5 MHz.


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