Integral representations over finite limits for quantum amplitudes

Fuente: arXiv
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Auteur principal: Straton, Jack C.
Format: Preprint
Publié: 2023
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author Straton, Jack C.
author_facet Straton, Jack C.
contents We extend prior work to derive three additional M-1-dimensional integral representations--over the interval $[0,1]$ --for products of M Slater orbitals that allows their magnitudes of coordinate vector differences (square roots of polynomials) $|{\bf x}_{1}-{\bf x}_{2}|=\sqrt{x_{1}^{2}-2x_{1}x_{2}\cosθ+x_{2}^{2}}$ to be moved from disjoint products of functions into a single quadratic form whose square my be completed. This provides more alternatives to Fourier transforms that introduce a 3M-dimensional momentum integral for those products of Slater orbitals, followed by another set of M-1-dimensional integral representations to combine those denominators into one denominator having a single (momentum) quadratic form. The current work is also slightly more compact than Gaussian transforms that introduce an M-dimensional integral for products of M Slater orbitals. We have found that two of these M-1-dimensional integral representations over the interval $[0,1]$ are numerically stable, as was the prior version having integrals running over the interval $[0,\infty]$, and one does not need to test for a sufficiently large upper integration limit. For analytical reductions of integrals arising from any of the three, however, there is the possible drawback for large M of there being fewer tabled integrals over $[0,1]$ than over $[0,\infty]$. These representations have integration variables within square roots as arguments of Macdonald functions. In a number of cases, these may be converted to Meijer G-functions for which a single tabled integral exists over the interval $[0,\infty]$ of the prior paper, and from which other forms may be found. Finally, we introduce a fourth integral representation that is not easily generalizable to large M, but may well provide a bridge for finding the requisite integrals for such Meijer G-functions over $[0,1]$.
format Preprint
id arxiv_https___arxiv_org_abs_2401_00136
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Integral representations over finite limits for quantum amplitudes
Straton, Jack C.
General Mathematics
44A20, 44A30, 81Q30, 81Q99, 33C10, 33C70, 33C60
We extend prior work to derive three additional M-1-dimensional integral representations--over the interval $[0,1]$ --for products of M Slater orbitals that allows their magnitudes of coordinate vector differences (square roots of polynomials) $|{\bf x}_{1}-{\bf x}_{2}|=\sqrt{x_{1}^{2}-2x_{1}x_{2}\cosθ+x_{2}^{2}}$ to be moved from disjoint products of functions into a single quadratic form whose square my be completed. This provides more alternatives to Fourier transforms that introduce a 3M-dimensional momentum integral for those products of Slater orbitals, followed by another set of M-1-dimensional integral representations to combine those denominators into one denominator having a single (momentum) quadratic form. The current work is also slightly more compact than Gaussian transforms that introduce an M-dimensional integral for products of M Slater orbitals. We have found that two of these M-1-dimensional integral representations over the interval $[0,1]$ are numerically stable, as was the prior version having integrals running over the interval $[0,\infty]$, and one does not need to test for a sufficiently large upper integration limit. For analytical reductions of integrals arising from any of the three, however, there is the possible drawback for large M of there being fewer tabled integrals over $[0,1]$ than over $[0,\infty]$. These representations have integration variables within square roots as arguments of Macdonald functions. In a number of cases, these may be converted to Meijer G-functions for which a single tabled integral exists over the interval $[0,\infty]$ of the prior paper, and from which other forms may be found. Finally, we introduce a fourth integral representation that is not easily generalizable to large M, but may well provide a bridge for finding the requisite integrals for such Meijer G-functions over $[0,1]$.
title Integral representations over finite limits for quantum amplitudes
topic General Mathematics
44A20, 44A30, 81Q30, 81Q99, 33C10, 33C70, 33C60
url https://arxiv.org/abs/2401.00136