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Hashim A. Yamani

Publications and source records attributed to Hashim A. Yamani.

7 recordsLinked to original sources
arXiv2025

Zernike polynomials from the tridiagonalization of the radial harmonic oscillator in displaced Fock states

We revisit the J-matrix method for the one dimensional radial harmonic oscillator (RHO) and construct its tridiagonal matrix representation within an orthonormal basis phi(z)n of L2 (R+);parametrized by a fixed z in the complex unit disc D and n = 0,1,2,.... Remarkably, for fixed n,and varying z in D, the system phi(z)n forms a family of Perelomov-type coherent states associated with the RHO. For each fixed n, the expansion of phi(z)n over the basis (fs) of eigenfunctions of the RHO yields coefficients cn,s(z; z) precisely given by two-dimensional complex Zernike polynomials. The key insight is that the algebraic tridiagonal structure of RHO contains the complete information about the bound state solutions of the two-dimensional Schrödinger operator describing a charged particle in a magnetic field (of strength proportional to B > 1/2) on the Poincaré disc D.

math-ph↗
arXiv2024

Generalized coherent states for the harmonic oscillator by the J-matrix method with an extension to the Morse potential

While dealing with the J-Matrix method for the harmonic oscillator to write down its tridiagonal matrix representation in an orthonormal basis of L2(R); we rederive a set of generalized coherent states (GCS) of Perelomov type labeled by points z of the complex plane C and depending on a positive integer number m The number states expansion of these GCS gives rise to coefficients that are complex Hermite polynomials whose linear superpositions provide eigenfunctions for the two-dimensional magnetic Laplacian associated with the mth Landau level. We extend this procedure to the Morse oscillator by constructing a new set of GCS of Glauber type.

quant-ph↗
arXiv2021

Coherent states associated with tridiagonal Hamiltonians

It has been shown that a positive semi-definite Hamiltonian H, that has a tridiagonal matrix representation in a given basis, can be represented in the form H = A†A, where A is a forward shift operator playing the role of an annihilation operator. Such representation endows H with rich supersymmetric properties yielding results analogous to those obtained by studying the Hamiltonian as a differential operator. Here, we study the coherent states which we define as being the eigenstates of the operator A. We explicitly find the expansion coefficients of these states in the given basis. We further identify a complete set of special coherent states which themselves can be used as basis. In terms of these special coherent states, we show that a general coherent state has the expansion form of a Lagrange interpolation scheme. As application of the developed formalism, we work out examples of systems having pure discrete, pure continuous, or mixed energy spectrum.

math-ph↗
arXiv2020

Coherent States of Systems with Pure Continuous Energy Spectra

While dealing with a Hamiltonian with continuous spectrum we use a tridiagonal method involving orthogonal polynomials to construct a set of coherent states obeying a Glauber-type condition. We perform a Bayesian decomposition of the weight function of the orthogonality measure to show that the obtained coherent states can be recast in the Gazeau-Klauder approach. The Hamiltonian of the $\ell$-wave free particle is treated as an example to illustrate the method.

math-ph↗
arXiv2018

Properties of shape-invariant tridiagonal Hamiltonians

It has been established that a positive semi-definite Hamiltonian,$H$, that has a tridiagonal matrix representation in a basis set, allows a definition of forward (and backward) shift operators that can be used to define the matrix representation of the supersymmetric partner Hamiltonian $H^{\left( +\right) \text{\ }}$ in the same basis. \ We show that if, additionally, the Hamiltonian has a shape invariant property, the matrix elements of the Hamiltonian are related in a such a way that the energy spectrum is known in terms of these elements. It is also possible to determine the matrix elements of the hierarchy of super-symmetric partner Hamiltonians. Additionally, we derive the coherent states associated with this type of Hamiltonians and illustrate our results with examples from well-studied shape-invariant Hamiltonians that also has tridiagonal matrix representation.

math-ph↗
arXiv2012

Extension and exact realization of the Heller's derivative rule

The accuracy of the Heller's derivative rule to calculate the numerical weights associated with discretized energy spectrum is enhanced by Broad's extension which adds (N-1) more interpolating points to the original N points. The extension scheme is then used to show how to realize the rule without any approximation.

math-ph↗