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M. Oulne

Publications and source records attributed to M. Oulne.

At least 37 records · Page 2Linked to original sources

Collective motion in triaxial nuclei within minimal length concept

The concept of minimal length, inspired by Heisenberg algebra, is applied to the geometrical collective Bohr- Mottelson model (BMM) of nuclei. With the deformed canonical commutation relation and the Pauli-Podolsky prescription, we have derived the quantized Hamiltonian operator for triaxial nuclei as we have previously done for axial prolate $γ$-rigid ones (M. Chabab et al., Phys. Lett. B 758 (2016) 212-218). By considering an infinite square well like potential in $β$ collective shape variable, the eigenvalues of the Hamiltonian are obtained in terms of zeros of Bessel functions of irrational order with an explicit dependence on the minimal length parameter. Moreover, the associated symmetry with the model that we have constructed here can be considered as a new quasi-dynamical critical point symmetries (CPSs) in nuclear structure. The theoretical results indicate a dramatic contribution (Low effect) of the minimal length to energy levels for lower values of the angular momentum and regular (significant effect) for higher values. In fact, these features show that the minimal length scenario which is useful in recognizing the properties of real deformed nuclei having high spins or strong rotations. Finally, numerical calculations are performed for some nuclei such as ${}^{124,128,130}$Xe and ${}^{114}$Pd revealing a qualitative agreement with the experimental data.

nucl-th↗

Davydov-Chaban Hamiltonian within the formalism of deformation-dependent effective mass for Davidson potential

In this work, we modify the Davydov-Chaban Hamiltonian describing the collective motion of a $γ$-rigid atomic nucleus by allowing the mass to depend on nuclear deformation. Exact analytical expressions are derived for energy spectra as well as normalized wave functions for Davidson potential. The model, called Z(4)-DDMD (Deformation Dependent Mass with Davidson potential), is achieved by using the Asymptotic Iteration Method (AIM). The numerical calculations for energy spectra and B(E2) transition probabilities are compared to the experimental data of $^{192-196}$Pt isotopes. The obtained results show an overall agreement with the experiment and an important improvement in respect to other models.

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Davydov-Chaban Hamiltonian with deformation-dependent mass term for γ = 30°

Motivation : Several theoretical comparisons with experimental data have recently pointed out that the mass tensor of the collective Bohr Hamiltonian cannot be considered as a constant and should be taken as a function of the collective coordinates. Method : The Davydov-Chaban Hamiltonian, describing the collective motion of γ-rigid atomic nuclei, is modified by allowing the mass to depend on the nuclear deformation. Moreover, the eigenvalue problem for this Hamiltonian is solved for Davidson potential and γ = 30° involving an Asymptotic Iteration Method (AIM). The present model is conventionally called Z(4)-DDM-D (Deformation Dependent Mass with Davidson potential), in respect to the so called Z(4) model. Results : Exact analytical expressions are derived for energy spectra and normalized wave functions, for the present model. The obtained results show an overall agreement with the experimental data for 108-116Pd, 128-132Xe, 136;138Ce and 190-198Pt and an important improvement in respect to other models. Prediction of a new candidate nucleus for triaxial symmetry is made. Conclusion : The dependence of the mass on the deformation reduces the increase rate of the moment of inertia with deformation, removing a main drawback of the model and leading to an improved agreement with the corresponding experimental data.

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Scattering states of Dirac particle equation with position dependent mass under the cusp potential

We solved the one-dimensional position-dependent mass Dirac equation in the presence of the cusp potential and reported the solutions in terms of the Whittaker functions. We have derived the reflection and transmission coefficients by making use of the matching conditions on the wave functions. The effect of position dependent mass on the reflection and transmission coefficients of the system is duly investigated.

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Scattering states of position-dependent mass Schrödinger equation with non central potential

In this paper, we study the time-independent Schrödinger equation within the formalism of position dependent effective mass. For a generalized decomposition of the non-central effective potential, the deformed Schrödinger equation can be easily solved analytically through separation of variables. The energy eigenvalues and the normalization constant of the radial wave functions are obtained, as well as the scattering phase shifts.

quant-ph↗

Excited collective states of nuclei within Bohr Hamiltonian with Tietz-Hua potential

In this paper, we present new analytical solutions of the Bohr Hamiltonian problem that we derived with the Tietz-Hua potential, here used for describing the β-part of the nuclear collective potential plus harmonic oscillator one for the γ-part. Also, we proceed to a systematic comparison of the numerical results obtained with this kind of β-potential with others which are widely used in such a framework as well as with the experiment. The calculations are carried out for energy spectra and electromagnetic transition probabilities for γ-unstable and axially symmetric deformed nuclei. In the same frame, we show the effect of the shape flatness of the β-potential beyond its minimum on transition rates calculations.

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Hartree-Fock-Bogoliubov calculation of ground state properties of even-even and odd Mo and Ru isotopes

In a previous work [Int. J. Mod. Phys. E 24, 1550073 (2015)], hereafter referred as paper I, we have investigated the ground-state properties of Nd, Ce and Sm isotopes within Hartree-Fock-Bogoliubov method with SLy5 skyrme force in which the pairing strength has been generalized with a new proposed formula. However, that formula is more appropriate for the region of Nd. In this work, we have studied the ground-state properties of both even-even and odd Mo and Ru isotopes. For this, we have used Hartree- Fock-Bogoliubov method with SLy4 skyrme force, and a new formula of the pairing strength which is more accurate for this region of nuclei. The results have been compared with available experimental data, the results of Hartree-Fock-Bogoliubov calculations based on the D1S Gogny effective nucleon-nucleon interaction and predictions of some nuclear models such as Finite Range Droplet Model (FRDM) and Relativistic Mean Field (RMF) theory.

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Nuclear shape phase transition within a conjonction of γ-rigid and γ-stable collective behaviours in deformation dependent mass formalism

In this paper, we present a theoretical study of a conjonction of $γ$-rigid and $γ$-stable collective motions in critical point symmetries of the phase transitions from spherical to deformed shapes of nuclei using exactly separable version of the Bohr Hamiltonian with deformation-dependent mass term. The deformation-dependent mass is applied simultaneously to $γ$-rigid and $γ$-stable parts of this famous collective Hamiltonian. Moreover, the $β$ part of the problem is described by means of Davidson potential, while the $γ$-angular part corresponding to axially symmetric shapes is treated by a Harmonic Osillator potential. The energy eigenvalues and normalized eigenfunctions of the problem are obtained in compact forms by making use of the asymptotic iteration method. The combined effect of the deformation-dependent mass and rigidity as well as harmonic oscillator stiffness parameters on the energy spectrum and wave functions is duly investigated. Also, the electric quadrupole transition ratios and energy sprectrum of some $γ$-stable and prolate nuclei are calculated and compared with the experimental data as well as with other theoretical models.

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Electric quadrupole transitions of the Bohr Hamiltonian with Manning-Rosen potential

Analytical expressions of the wave functions are derived for a Bohr Hamiltonian with the Manning{Rosen potential in the cases of γ-unstable nuclei and axially symmetric prolate deformed ones with γ=0. By exploiting the results we have obtained in a recent work on the same theme Ref. [1], we have calculated the B(E2) transition rates for 34 γ-unstable and 38 rotational nuclei and compared to experimental data, revealing a qualitative agreement with the experiment and phase transitions within the ground state band and showing also that the Manning-Rosen potential is more appropriate for such calculations than other potentials.

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On γ-rigid regime of the Bohr-Mottelson Hamiltonian in the presence of a minimal length

A prolate γ-rigid regime of the Bohr-Mottelson Hamiltonian within the minimal length formalism, involving an infinite square well like potential in β collective shape variable, is developed and used to describe the spectra of a variety of vibrational-like nuclei. The effect of the minimal length on the energy spectrum and the wave function is duly investigated. Numerical calculations are performed for some nuclei revealing a qualitative agreement with the available experimental data.

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Closed analytical solutions of the d-dimensional Schrödinger equation with deformed Woods-Saxon potential plus double ring-shaped potential

By employing the Pekeris approximation, the D-dimensional Schrödinger equation is solved for the nuclear deformed Woods-Saxon potential plus double ring-shaped potential within the framework of the Asymptotic Iteration Method (AIM). The energy eingenvalues are given in a closed form and the corresponding normalized eigenfunctions are obtained in terms of hypergeometric functions. Our general results reproduce many predictions obtained in the literature, using the Nikiforov-Uvarov method (NU) and the Improved Quantization Rule approach, particulary those derived by considering Woods-Saxon potential without deformation and/or without ring shape interaction.

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Variation and Series Approach to the Thomas-Fermi Equation

The Thomas - Fermi equation describing the screening of the Coulomb potential inside heavy neutral atoms is reconsidered. An accurate representation for its numerical solution was obtained by means of the variational principle. The proposed new solution has more precise asymptotic behaviour at large distances from the origin and allows us to obtain the exact value of the initial slope. The obtained new variational solution can also be developed in power series similar to the Baker's ones but more precise even than some series solutions that have been recently obtained within the homotopy analysis method and a modified variational method.

physics.comp-ph↗

Vibrational and rotational excited states within Bohr Hamiltonian with deformation-dependent mass formalism

In a recent work (Phys.Rev.C84, 044321, 2011) M.J. Ermamatov and P.R. Fraser have studied rotational and vibrational excited states of axially symmetric nuclei within the Bohr Hamiltonian with different mass parameters. However, the energy formula that the authors have used contains some inaccuracies. So, the numerical results they obtained seem to be controversial. In this paper, we revisit all calculations related to this problem and determine the appropriate formula for the energy spectrum. Moreover, in order to improve such calculations, we reconsider this problem within the framework of the deformation dependent mass formalism. Also, unlike the work of Bonatsos et al. (Phys.Rev.C83, 044321, 2011) where the mass parameter has not been considered, we will show the importance of this parameter and its effect on numerical predictions.

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Bohr Hamiltonian with Hulth?en plus Ring shaped potential for triaxial nuclei

In this paper, we solve the eigenvalues and eigenvectors problem with Bohr collective Hamil- tonian for triaxial nuclei. The ? beta part of the collective potential is taken to be equal to Hulth?en potential while the gamma part is defined by a new generalized potential obtained from a ring shaped one. Analytical expressions for spectra and wave functions are derived by means of a recent version of the asymptotic iteration method and the usual approximations. The calculated energies and B(E2) transition rates are compared with experimental data and the available theoretical results in the literature.

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Closed analytical solutions of Bohr Hamiltonian with Manning-Rosen potential model

In the present work, we have obtained closed analytical expressions for eigenvalues and eigenfunctions of the Bohr Hamiltonian with the Manning-Rosen potential for γ-unstable nuclei as well as exactly separable rotational ones with γ=0. Some heavy nuclei with known \b{eta} and γ bandheads have been fitted by using two parameters in the ν-unstable case and three parameters in the axially symmetric prolate deformed one. A good agreement with experimental data has been achieved.

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Exact solutions of Deformed Schrodinger Equation with a class of non central physical potentials

In this paper we present exact solutions of Schrodinger equation (SE) for a class of non central physical potentials within the formalism of position-dependent effective mass. The energy eigenvalues and eigenfunctions of the bound-states for the Schrodinger equation are obtained analytically by means of asymptotic iteration method (AIM) and easily calculated through a new generalized decomposition of the effective potential allowing easy separation of the coordinates. Our results are in excellent agreement with other works in the literature.

math-ph↗

Analytic l-state solutions of the Klein-Gordon equation for q-deformed Woods-Saxon plus generalized ring shape potential

The analytical expressions for the eigenvalues and eigenvectors of the Klein-Gordon equation for q-deformed Woods-Saxon plus new generalized ring shape potential are derived within the asymptotic iteration method. The obtained eigenvalues are given in a closed form and the corresponding normalized eigenvectors, for any l, are formulated in terms of the generalized Jacobi polynomials for the radial part of the Klein-Gordon equation and associated Legendre polynomials for its angular one. When the shape deformation is canceled, we recover the same solutions previously obtained by the Nikiforov-Uvarov method for the standard spherical Woods-Saxon potential. It is also shown that, from the obtained results, we can derive the solutions of this problem for Hulthen potential.

quant-ph↗