arXiv subjects

H. Sabri

Publications and source records attributed to H. Sabri.

At least 19 recordsLinked to original sources

arXiv2025

Effects of vibration and rigidity modes of motion on the spectral statistics of spherical nuclei

In this paper, we investigated the effects of \b{eta}-vibration and \b{eta}-rigidity on the energy levels from the viewpoint of statistical fluctuations of nuclear systems. To this aim, a parameter-free collective solution of the Bohr Hamiltonian in the five-dimensional harmonic oscillator potential with a linear energy dependence and an asymptotic limit of the slope are used to determine all of the observed normal states in even-even nuclei with ~ 2.00 - 2.15 ratio in the A ~ 90 -140 mass region. Different sequences are prepared of the energy levels, both experimental values and theoretical predictions, which are categorized as their spin-parity, \b{eta} oscillator quanta, and seniority numbers and analyzed in the framework of random matrix theory to show their statistical situation in comparison with regular and correlated limits. Also, up to 2226 levels with the same 2+ spin-parity assignment are determined for different systems in which the stiffness parameter for them changed between a = 0 and a =1 limits and then analyzed in the same process. The results showed a transition between correlated behavior and regularity when the rigidity increased in considered systems. Also, there are apparent relations between the chaocity degrees of considered sequences and the considered criteria for classifications.

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arXiv2023

The exact description of intruder states in $^{112}$Cd nucleus by using a mixing formalism based on $SU(1,1)$ transitional Hamiltonian and $O(6)$-Casimir operator

In this paper, we used a transitional Hamiltonian which has $U(5)\leftrightarrow(6)$ transition to improve theoretical predictions for energy spectra and quadrupole transition rates of $^{112}$Cd nucleus. To this aim, the transitional Hamiltonian in the affine $SU(1,1)$ algebra has been extended by adding the $O(6)$-Casimir operator and mixing Hamiltonian to increase exactness in the description of 4$^+_2$ and 2$^+_3$ intruder levels of this nucleus. We also considered the wave functions of both regular and intruder states, as a combination in the $N$ and $N+2$ boson spaces. The results confirm the advantages of using such mixing approaches and describing the energy and transition rates with high accuracy

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arXiv2017

Study of shape coexistence in the 180-190Hg isotopes by SO(6) representation of eigenstates

In this paper, we have studied the shapes coexistence in the 180-190Hg isotopes. The SO(6) representation of eigenstates and a transitional Hamiltonian in the Interacting Boson Model are used to consider the evolution from prolate to oblate shapes for systems with total boson number N = 9-12. Parameter free (up to overall scale factors) predictions for energy spectra and quadrupole transition rates are found to be in good agreement with experimental counterparts. The results for the control parameter of transitional Hamiltonian offer a combination of spherical and deformed shapes in these Hg isotopes and also more deviation from SO(6) limit is observed when the quadrupole deformation is decreased. Also, there are some suggestion about the expectation values of operator which are determined in the first state of ground, beta and gamma bounds and the control parameter of model.

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arXiv2016

A transition in the spectral statistics of quantum optical model by different electromagnetic fields

The effects of the quantized electromagnetic fields on the spectral statistics of two-level atoms are considered. We have used the Berry- Robnik distribution and Maximum Likelihood estimation technique to analyze the effect of mean photon and two level atoms numbers and also the quantum number of considered states. Results suggest the intensity of electromagnetic fields as control parameter which the spectral statistics change due to its variation in the 0-1200 region. Also, we observed the universality in the spectral statistics of considered systems when the number of two level atoms is approached to unrealistic limits and there are some suggestions about the effect of the quantum number of selected levels and the atom-field coupling constant on level statistics.

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arXiv2016

Energy spectra and quadrupole transition probabilities of 124-130Ba

In this paper, we have studied the energy spectra and B(E2) transition probabilities of 124-130Ba isotopes in the shape phase transition region between the spherical and gamma unstable deformed shapes. We have used a transitional Interacting Boson Model Hamiltonian which is based on affine SU(1,1) Lie Algebra in the both IBM-1 and 2 versions and also the Catastrophe theory in combination with a coherent state formalism to generate energy surfaces and determine the exact values of control parameters. Our results for control parameters suggest a combination of U(5) and SO(6) dynamical symmetries in this isotopic chain. Also, the theoretical predictions can be rather well reproduce the experimental counterparts when the control parameter is approached to the SO(6) limit.

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arXiv2015

Investigation of shape coexistence in 118-128Te isotopes

In this paper, we have considered the interplay between phase transitions and configuration mixing of intruder excitations in the 118-128Te isotopes. A transitional interacting boson model Hamiltonian in both IBM-1 and IBM-2 versions which are based on affine Lie Algebra are employed to describe the evolution from spherical to deformed gamma unstable shapes along the chain of Te isotopes. The excitation energies, B(E0) and B(E2) transition rates are rather well reproduced in comparison with experimental counterparts when the weight of SO(6) limit is increased in Hamiltonian. Also our results show obvious relations between the configuration mixing ratio and quadrupole, hexadecapole and hexacontatetrapole deformation values in this isotopic chain.

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arXiv2015

Spectral statistics of rare-earth nuclei: Investigation of shell model configuration effect

The spectral statistics of even-even rare-earth nuclei are investigated by using all the available empirical data for Ba, Ce, Nd, Sm, Gd, Dy, Er, Yb and Hf isotopes. The Berry- Robnik distribution and Maximum Likelihood estimation technique are used for analyses. An obvious deviation from GOE is observed for considered nuclei and there are some suggestions about the effect due to mass, deformation parameter and shell model configurations.

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arXiv2014

Investigation of low-lying energy spectra for deformed prolate nuclei via partial dynamical SU(3) symmetry

We consider the possibility of identifying nuclei exhibiting the partial dynamical SU(3) symmetry (SU(3)-PDS) as those having excitation energy ratio R(4/2)>3.00 . For this purpose, the level energy spectra of a set of 51 nuclei in the rare earth and actinide regions which presenting an axially deformed prolate rotational structure were analyzed via nuclear partial dynamical SU(3) symmetry in the framework of interacting boson model, to see if the SU(3)-PDS is broadly applicable, and where, how, and in which nuclei it breaks down. Overall, the PDS works very well, the predictions of such intermediate symmetry structure for energy spectrum were compared with the most recent experimental data and an acceptable degree of agreement is achieved. We conclude that PDS predictions have a more regular behavior in description of axially deformed prolate rotational nuclei than DS, which may lead to accurate predictions of such nuclei, and hence play a significant role in understanding the regular behavior of complex nuclei.

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arXiv2013

Investigation of Nuclear Phase transition with using Landau Theory

In this paper, Landau theory for phase transitions is shown to be a useful approach also for quantal system such as atomic nucleus. A detailed analysis of critical exponents of ground state quantum phase transition between and limits of interacting boson model is presented.

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arXiv2013

Pairing Effect on Spectral Statistics of Even and Odd Mass Nuclei

The interplay of pairing is explored for the spectral statistics of nuclear systems with emphasis on the nearest neighbor spacing distributions by employing the kernel density and maximum likelihood estimation techniques. Different sequences prepared by all the available empirical data for low-lying energy levels of even and odd-mass nuclei in the 34 < A < 206 mass region. A deviation to more regular dynamics is apparent for even-mass nuclei in compare to odd-mass ones, and there are suggestions of effects due to unclosed proton shells on more chaotic dynamics.

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arXiv2012

Description of Even-Even Xe isotopes in the transitional region of IBM

Properties of Xe isotopes isotopes are studied in the U(5)<->O(6) transitional region of Interacting Boson Model (IBM-1). The energy levels and B(E2)transition rates are calculated via the affine SU(1,1)Lie Algebra. The agreement with the most recent experimental is acceptable. The evaluated Hamiltonian control parameters suggest a spherical to (/gamma)-soft shape transition and propose the Xe(A=130)nucleus as the best candidate for the E(5)symmetry.

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arXiv2012

Description of Dy (A=160)nucleus by Partial Dynamical SU(3) Symmetry

We considered the characteristic features of SU(3) partial dynamical symmetry in the interacting boson model framework to demonstrate the relevance of this technique in the nuclear spectroscopy of Dy (A=160) nucleus. The predictions of SU(3)-PDS for energy spectrum and B(E2)transition probabilities were compared with the most recent experimental data which an acceptable degree of agreement is achieved.

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arXiv2012

Level Statistics of SU(3)-SU(3)* Transitional Region

The level statistics of SU(3)-SU(3)* transitional region of IBM is described by the nearest neighbor spacing distribution statistics. The energy levels are determined by using the SO(6)representation of eigenstates. By employing the MLE technique, the parameter of Abul-Magd distribution is estimated where suggest less regular dynamics for transitional region in compare to dynamical symmetry limits. Also, the O(6)dynamical symmetry which is known as the critical point of this transitional region, describes a deviation to more regular dynamics.

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arXiv2012

Investigation of Level Statistics by Generalized Brody Distribution and Maximum Likelihood Estimation Method

With generalizing the Brody distribution to include the Poisson, GOE and GUE limits and with employing the maximum likelihood estimation technique, the spectral statistics of different sequences were considered in the nearest neighbor spacing statistics framework. The ML-based estimated values for the parameters of generalized distribution propose more precisions in compare to the predictions of other distributions. The transition in the level spacing statistics of different systems were described by the distances of ML-based predictions for generalized distribution to three limits which determined by KLD measures.

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arXiv2012

Level Statistics of Stable and Radioactive Nuclei

The spectral statistics of nuclei undergo through the major forms of radioactive decays ((α)(β^-), and(β^+) (or EC)) and also stable nuclei are investigated. With employing the MLE technique in the nearest neighbor spacing framework, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values propose a deviation to more regular dynamics in sequences constructed by stable nuclei in compare to unstable ones. In the same mass regions, nuclei transmitted through (α)decay explore less regularity in their spectra in compare to other radioactive nuclei.

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arXiv2012

A Description of Hg (200-204)isotopes in the SU(3)<->SU(3)* Transitional Region

With employing the SO(6)representation of eigenstates, the energy spectra and quadrupole transition rates of SU(3)<->SU(3)* transition region are considered for systems with total boson number N=2,3,4. The apparent level crossing and significant variations in the transition rates for X=0, namely, the critical point of transitional Hamiltonian, suggest a phase transition between these limits. The parameter free (up to overall scale factors) predictions for spectra and B(E2)rates by X=0are found to be in good agreement with those for nuclei provide empirical evidences for O(6)dynamical symmetry, namely Hg(200-204)isotopes.

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arXiv2012

An Affine SU(1,1)Description of Even-Even Cd (106-122) Isotopes in the Transitional Region of IBM

In this paper, the properties of Cd(106-122)isotopes are considered in the U(5)-SO(6)transitional region of IBM1. With employing a transitional Hamiltonian which is based on affine SU(1,1)Lie Algebraic technique, the energy levels and B(E2)transition rates are calculated. The results are compared with the most recent experimental values where an acceptable degree of agreement is achieved. Also, the energy ratios, control parameters and empirical two neutron separation energies suggest spherical to gamma soft shape transitions in these nuclei where the Cd (114,122)nuclei are considered as the best candidates for the E(5)critical symmetry.

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arXiv2012

Spectral fluctuation properties of spherical nuclei

The spectral fluctuation properties of spherical nuclei are considered by use of NNSD statistic. With employing a generalized Brody distribution included Poisson, GOE and GUE limits and also MLE technique, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values and also KLD measures propose a non regular dynamic. Also, spherical odd-mass nuclei in the mass region, exhibit a slight deviation to the GUE spectral statistics rather than the GOE.

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