Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators

<p dir="ltr">In resumming a divergent series, one is frequently confronted with situations where predictions from traditional resummation techniques might not accurate when considering strong-coupling values. Besides, in literature, we barely can find a resummation algorithm for whic...

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Main Author: I.S. Elkamash (16810689) (author)
Other Authors: Hamdi M. Abdelhamid (16810692) (author), Abouzeid M. Shalaby (16810695) (author)
Published: 2023
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author I.S. Elkamash (16810689)
author2 Hamdi M. Abdelhamid (16810692)
Abouzeid M. Shalaby (16810695)
author2_role author
author
author_facet I.S. Elkamash (16810689)
Hamdi M. Abdelhamid (16810692)
Abouzeid M. Shalaby (16810695)
author_role author
dc.creator.none.fl_str_mv I.S. Elkamash (16810689)
Hamdi M. Abdelhamid (16810692)
Abouzeid M. Shalaby (16810695)
dc.date.none.fl_str_mv 2023-10-01T00:00:00Z
dc.identifier.none.fl_str_mv 10.1016/j.aop.2023.169427
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Entire_hypergeometric_approximants_for_the_ground_state_energy_perturbation_series_of_the_quartic_sextic_and_octic_anharmonic_oscillators/24166521
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Physical sciences
Classical physics
Hypergeometric algorithim
Divergent series
Large-order behavior
Strong coupling behavior
dc.title.none.fl_str_mv Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <p dir="ltr">In resumming a divergent series, one is frequently confronted with situations where predictions from traditional resummation techniques might not accurate when considering strong-coupling values. Besides, in literature, we barely can find a resummation algorithm for which the convergence is faster for stronglydivergent ( Gevrey − k , k > 1) series than a divergent one ( Gevrey − 1 ). In this work, we use appropriate hypergeometric functions to approximate a divergent series ( n! large order growth factor) and strongly-divergent series ( (2n)! and (3n)! large order growth factors). We found that the convergence of the predicted non-perturbative parameters to their exact values is faster for the challenging Gevrey−3 than the Gevrey−2 series which in turn is faster than the divergent Gevrey − 1 series. To explain such interesting feature, we suggest a type of analytic continuation where the parametrized divergent hypergeometric series is represented as a finite sum over entire hypergeometric functions. The algorithm is applied to sum the weak-coupling series of the ground state energy of the quartic (divergent), sextic (Gevrey−2) and Octic (Gevrey−3) anharmonic oscillators. Accurate results are obtained for the ground state energy as well as the predicted non-perturbative parameters. While traditional resummation techniques fail to give reliable results for large coupling values, our algorithm gives the expected limit as the coupling goes to infinity.</p><h2>Other Information</h2><p dir="ltr">Published in: Annals of Physics<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.aop.2023.169427" target="_blank">https://dx.doi.org/10.1016/j.aop.2023.169427</a></p>
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identifier_str_mv 10.1016/j.aop.2023.169427
network_acronym_str Manara2
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oai_identifier_str oai:figshare.com:article/24166521
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spelling Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillatorsI.S. Elkamash (16810689)Hamdi M. Abdelhamid (16810692)Abouzeid M. Shalaby (16810695)Physical sciencesClassical physicsHypergeometric algorithimDivergent seriesLarge-order behaviorStrong coupling behavior<p dir="ltr">In resumming a divergent series, one is frequently confronted with situations where predictions from traditional resummation techniques might not accurate when considering strong-coupling values. Besides, in literature, we barely can find a resummation algorithm for which the convergence is faster for stronglydivergent ( Gevrey − k , k > 1) series than a divergent one ( Gevrey − 1 ). In this work, we use appropriate hypergeometric functions to approximate a divergent series ( n! large order growth factor) and strongly-divergent series ( (2n)! and (3n)! large order growth factors). We found that the convergence of the predicted non-perturbative parameters to their exact values is faster for the challenging Gevrey−3 than the Gevrey−2 series which in turn is faster than the divergent Gevrey − 1 series. To explain such interesting feature, we suggest a type of analytic continuation where the parametrized divergent hypergeometric series is represented as a finite sum over entire hypergeometric functions. The algorithm is applied to sum the weak-coupling series of the ground state energy of the quartic (divergent), sextic (Gevrey−2) and Octic (Gevrey−3) anharmonic oscillators. Accurate results are obtained for the ground state energy as well as the predicted non-perturbative parameters. While traditional resummation techniques fail to give reliable results for large coupling values, our algorithm gives the expected limit as the coupling goes to infinity.</p><h2>Other Information</h2><p dir="ltr">Published in: Annals of Physics<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.aop.2023.169427" target="_blank">https://dx.doi.org/10.1016/j.aop.2023.169427</a></p>2023-10-01T00:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1016/j.aop.2023.169427https://figshare.com/articles/journal_contribution/Entire_hypergeometric_approximants_for_the_ground_state_energy_perturbation_series_of_the_quartic_sextic_and_octic_anharmonic_oscillators/24166521CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/241665212023-10-01T00:00:00Z
spellingShingle Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
I.S. Elkamash (16810689)
Physical sciences
Classical physics
Hypergeometric algorithim
Divergent series
Large-order behavior
Strong coupling behavior
status_str publishedVersion
title Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
title_full Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
title_fullStr Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
title_full_unstemmed Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
title_short Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
title_sort Entire hypergeometric approximants for the ground state energy perturbation series of the quartic, sextic and octic anharmonic oscillators
topic Physical sciences
Classical physics
Hypergeometric algorithim
Divergent series
Large-order behavior
Strong coupling behavior