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arXiv:1912.10844

Numerical and Analytical Study of the Bound States of the $-α/x^2$ Potential

Thanh Nguyen, F. Marsiglio

Published Dec 19, 2019• 0 citations
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Abstract

The quantum mechanical bound states of the $-α/x^2$ potential are truly anomalous. We revisit this problem by adopting a slightly modified version of this potential, one that adopts a cutoff in the potential arbitrarily close to the origin. The resulting solutions are completely well-defined and ``normal.'' We present results here as a case study in undergraduate research --- two independent methodologies are used: one analytical (with very unfamiliar non-elementary functions) and one numerical (with very straightforward methodology). These play complementary roles in arriving at solutions and achieving insights in this problem.

DOI
10.48550/arxiv.1912.10844

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The quantum mechanical bound states of the −α/x2-α/x^2−α/x2 potential are truly anomalous. We revisit this problem by adopting a slightly modified version of this potential, one that adopts a cutoff in the potential arbitrarily close to the origin. The resulting solutions are completely well-defined and ``normal.'' We present results here as a case study in undergraduate research --- two independent methodologies are used: one analytical (with very unfamiliar non-elementary functions) and one numerical (with very straightforward methodology). These play complementary roles in arriving at solutions and achieving insights in this problem.
The quantum mechanical bound states of the −α/x2 potential are truly anomalous. We revisit this problem by adopting a slightly modified version of this potential, one that adopts a cutoff in the potential arbitrarily close to the origin. The resulting solutions are completely well-defined and “normal,” and provide us with additional insight into the solutions of the “bare” −α/x2 potential. We present results here as a case study in undergraduate research—two independent methodologies are used: one analytical (albeit with very unfamiliar non-elementary functions) and one numerical (with a very straightforward methodology). These play complementary roles in arriving at solutions and achieving insights into this problem.
Semi-analytic version of shooting method and the bound states in non-analytic potential V(x)=−g2exp⁡(−∣x∣)V(x)= -g^2\exp (-|x|)V(x)=−g2exp(−∣x∣)
People construct quantum bound states either non-numerically (in not too many exceptional cases) or, in general, numerically (mainly using majorization or discretization techniques). We point out that there exists a class of interactions "in between". Being, in conventional terminology, neither exactly solvable nor purely numerical. The idea is illustrated by the elementary exponential-well toy-model potential V(x)=−g2exp⁡(−∣x∣)V(x)= -g^2\exp (-|x|)V(x)=−g2exp(−∣x∣).
The procedure commonly used in textbooks for determining the eigenvalues and eigenstates for a particle in an attractive Coulomb potential is not symmetric in the way the boundary conditions at r = 0 and r → ∞ are considered. We highlight this fact by solving a model for the Coulomb potential with a cutoff (representing the finite extent of the nucleus). In the limit that the cutoff is reduced to zero, we recover the standard result, albeit in a non-standard way. This example is used to emphasize that a more consistent approach to solving the Coulomb problem in quantum mechanics requires an examination of the non-standard solution. The end result is, of course, the same.
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In this study, we focus on investigating the exact relativistic bound-state spectra for supersymmetric, PT -supersymmetric and non -Hermitian versions of the q -deformed parameter Hulthén potential. The Hamiltonian hierarchy mechanism, namely the factorization method , is adopted within the framework of SUSYQM. This algebraic approach is used in solving the Klein-Gordon equation with the potential cases. The results obtained analytically by executing the straightforward calculations are in consistent forms for certain values of q . Achieving the results may have a particular interest for such applications. That is, they can be involved in determining the quantum structural properties of molecules for ro-vibrational states, and optical spectra characteristics of semiconductor devices with regard to the lattice dynamics. They are also employed to construct the broken or unbroken case of the supersymmetric particle model concerning the interaction between the elementary particles.