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Omar Mustafa

Publications and source records attributed to Omar Mustafa.

At least 109 records · Page 6Linked to original sources
arXiv2003

On spectroscopic structure of two interacting electrons in a quantum dot

The shifted 1/N expansion technique, used by El-Said (Phys. Rev. B 61, 13026 (2000)), to study the relative Hamiltonian of two interacting electrons confined in a quantum dot, is investigated. El-Said's results from SLNT are revised and results from an alternative method are also reported. The distinctive role of the central spike term, $(m^2-1/4)/q^2$, in determinig the spectral properties of the above problem is shown, moreover.

cond-mat.soft↗
arXiv2002

Asymptotic solvability of an imaginary cubic oscillator with spikes

For the PT symmetric potential of Dorey, Dunning and Tateo we show that in the large angular momentum (i.e., strongly spiked) limit the low-lying eigenstates of this popular non-Hermitian problem coincide with the shifted Hermitian harmonic oscillators calculated at the zero angular momentum. This type of an approximate Hermitization is valid in all the domain where the spectrum of energies remains real. It proves very efficient numerically. The construction is asymmetric with respect to the sign of the subdominant square-root spike, and exhibits a discontinuity at the point where the PT symmetric regularization vanishes.

hep-th↗
arXiv2001

On the quasi - exact solvability of a singular potential in D - dimensions; confined and unconfined

The D -dimensional quasi - exact solutions for the singular even - power anharmonic potential $V(q)=aq^2+bq^{-4}+cq^{-6}$ are reported. We show that whilst Dong and Ma's [5] quasi - exact ground - state solution (in D=2) is beyond doubt, their solution for the first excited state is exotic. Quasi - exact solutions for the ground and first excited states are also given for the above potential confined to an impenetrable cylindrical (D=2) or spherical (D=3) wall.

math-ph↗
arXiv2001

On the correlation energies for two interacting electrons in a parabolic quantum dot

The correlation energies for two interacting electrons in a parabolic quantum dot are studied via a pseudo-perturbation recipe. It is shown that the central spike term, ($m^2-1/4)/r^2$, plays a distinctive role in determining the spectral properties of the above problem. The study is carried out for a wide range of the Coulomb coupling strength $λ$ relative to the confinement.

cond-mat.soft↗
arXiv2001

Magnetic fingerprints on the spectra of one-electron and two-electrons interacting in parabolic quantum dots

Magnetic fingerprints on the spectra of an interacting electron with a negatively charged ion in a parabolic quantum dot (QD), and of two interacting electrons in such a dot, are investigated via a pseudoperturbative methodical proposal. The effect of ion-electron and electron-electron interactions on the spectra are studied. The effect of the symmetry of such problem is emphasized. Compared to those obtained by Zhu et al. [6], via a series solution, the results are found in excellent accord. Higher excited - states are also reported.

math-ph↗
arXiv2001

Pseudo perturbative expansion method; the non-polynomial, cutoff - Coulomb, and Coulomb plus logarithmic potentials

We propose a new analytical method to solve for nonexactly soluble Schrodinger equation via expansions through some existing quantum numbers. Successfully, it is applied to the rational non-polynomial oscillator potential. Moreover, a conclusion reached by Scherrer et al. [2], via matrix continued fractions method, that the shifted large N expansion method leads to dubious accuracies is investigated. The cutoff - Coulomb and Coulomb plus logarithmic potentials are also investigated.

math-ph↗
arXiv2001

Part of the D - dimensional anharmonic oscillator spectra

The pseudoperturbative shifted - $l$ expansion technique PSLET [12,16] is generalized for states with arbitrary number of nodal zeros. Interdimensional degeneracies, emerging from the isomorphism between angular momentum and dimensionality of the central force Schrödinger equation, are used to construct part of the D - dimensional anharmonic oscillator bound - state spectra. PSLET results are found to compare excellently with those from a series [5], exact and open perturbation [9] solutions.

math-ph↗
arXiv2000

Bound - states for truncated Coulomb potentials

The pseudoperturbative shifted - $l$ expansion technique PSLET is generalized for states with arbitrary number of nodal zeros. Bound- states energy eigenvalues for two truncated coulombic potentials are calculated using PSLET. In contrast with shifted large-N expansion technique, PSLET results compare excellently with those from direct numerical integration.

math-ph↗
arXiv2000

Energy levels of neutral atoms via a new perturbation method

The energy levels of neutral atoms supported by Yukawa potential, $V(r)=-Z exp(-αr)/r$, are studied, using both dimensional and dimensionless quantities, via a new analytical methodical proposal (devised to solve for nonexactly solvable Schrodinger equation). Using dimensionless quantities, by scaling the radial Hamiltonian through $y=Zr$ and $α^{'}=α/Z$, we report that the scaled screening parameter $α^{'}$ is restricted to have values ranging from zero to less than 0.4. On the other hand, working with the scaled Hamiltonian enhances the accuracy and extremely speeds up the convergence of the energy eigenvalues. The energy levels of several new eligible scaled screening parameter $α^{'}$ values are also reported.

math-ph↗
arXiv2000

Part of the D - dimensional Spiked harmonic oscillator spectra

The pseudoperturbative shifted - l expansion technique PSLET [5,20] is generalized for states with arbitrary number of nodal zeros. Interdimensional degeneracies, emerging from the isomorphism between angular momentum and dimensionality of the central force Schrodinger equation, are used to construct part of the D - dimensional spiked harmonic oscillator bound - states. PSLET results are found to compare excellenly with those from direct numerical integration and generalized variational methods [1,2].

math-ph↗
arXiv2000

Anharmonic oscillators energies via artificial perturbation method

A new pseudoperturbative (artificial in nature) methodical proposal [15] is used to solve for Schrodinger equation with a class of phenomenologically useful and methodically challenging anharmonice oscillator potentials V(q)=α_o q^2 + αq^4. The effect of the [4,5] Pade' approximant on the leading eigenenergy term is studied. Comparison with results from numerical (exact) and several eligible (approximation) methods is made.

quant-ph↗
arXiv1999

2D H-atom in an arbitrary magnetic field via pseudoperturbation expansions through the quantum number l

The pseudoperturbative shifted-l expansion technique (PSLET) is introduced to determine nodeless states of the 2D Schrodinger equation with an arbitrary cylindrically symmetric potentials. Exact energy eigenvalues and eigenfunctions for the 2D Coulomb and harmonic oscillator potentials are reproduced. Moreover, exact energy eigenvalues, compared to those obtained by numerical solution [11], were obtained for the hybrid of the 2D Coulomb and oscillator potentials.

math-ph↗
arXiv1999

Nonrelativistic shifted-l expansion technique for three- and two-dimensional Schrodinger equation

The shifted-l expansion technique (SLET) has been developed to get eigenvalues of Schrodinger equation in three (3D) and two dimensions (2D). SLET simply consists of 1/\bar{l} as a perturbation parameter, where \bar{l}=l-β, βis a suitable shift, l is the angular momentum quantum number for 3D-case, l=|m| for the 2D-case, and m is the magnetic quantum number. Unlike the shifted large-N expansion theory (SLNT), SLET seems to be applicable to a wider number of problems of significant interest in physics.

math-ph↗
arXiv1999

Relativistic shifted-l expansion technique for Dirac and Klein-Gordon equations

The shifted-i expansion technique (SLET) is extended to solve for Dirac particle trapped in spherically symmetric scalar and/or 4-vector potentials. A parameter λ=0,1 is introduced in such a way that one can obtain the Klein-Gordon (KG) bound states from Dirac bound states. The 4-vector Coulomb, the scalar linear, and the equally mixed scalar and 4-vector power-law potentials are used in KG and Dirac equations. Exact numerical results are obtained for the 4-vector Coulomb potential in both KG and Dirac equations. Highly accurate and fast converging results are obtained for the scalar linear and the equally mixed scalar and 4-vector power-law potentials.

math-ph↗