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Perturbative Expansion
, 1997
"... We review how a specific resummation of the socalled “deltaexpansion”, applied to the QCD Lagrangian, transforms the ordinary perturbative expansion in αs into an expansion in an arbitrary mass parameter, around the basic scale ¯ Λ. When applied to the pole mass, the resulting expression may be in ..."
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We review how a specific resummation of the socalled “deltaexpansion”, applied to the QCD Lagrangian, transforms the ordinary perturbative expansion in αs into an expansion in an arbitrary mass parameter, around the basic scale ¯ Λ. When applied to the pole mass, the resulting expression may
Perturbative expansion of Chern–Simons theory
, 2006
"... An overview of the perturbative expansion of the Chern–Simons path integral is given. The main goal is to describe how trivalent graphs appear: as they already occur in the perturbative expansion of an analogous finitedimensional integral, we discuss this case in detail. ..."
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An overview of the perturbative expansion of the Chern–Simons path integral is given. The main goal is to describe how trivalent graphs appear: as they already occur in the perturbative expansion of an analogous finitedimensional integral, we discuss this case in detail.
On the Convergence of the Usual Perturbative Expansions
, 1997
"... The study of the convergence of power series expansions of energy eigenvalues for anharmonic oscillators in quantum mechanics differs from general understanding, in the case of quasiexactly solvable potentials. They provide examples of expansions with finite radius and suggest techniques useful to ..."
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The study of the convergence of power series expansions of energy eigenvalues for anharmonic oscillators in quantum mechanics differs from general understanding, in the case of quasiexactly solvable potentials. They provide examples of expansions with finite radius and suggest techniques useful
On causality, unitarity and perturbative expansions
"... We present a pedagogical case study how to combine microcausality and unitarity based on a perturbative approach. The method we advocate constructs an analytic extrapolation of partialwave scattering amplitudes that is constrained by the unitarity condition. Suitably constructed conformal mapping ..."
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We present a pedagogical case study how to combine microcausality and unitarity based on a perturbative approach. The method we advocate constructs an analytic extrapolation of partialwave scattering amplitudes that is constrained by the unitarity condition. Suitably constructed conformal
Analytic continuation and perturbative expansions in QCD
"... Starting from the divergence pattern of perturbative quantum chromodynamics, we propose a novel, nonpower series replacing the standard expansion in powers of the renormalized coupling constant a. The coefficients of the new expansion are calculable at each finite order from the Feynman diagrams, w ..."
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Starting from the divergence pattern of perturbative quantum chromodynamics, we propose a novel, nonpower series replacing the standard expansion in powers of the renormalized coupling constant a. The coefficients of the new expansion are calculable at each finite order from the Feynman diagrams
Perturbation Expansions in Polynomial Root Tracking
 University of Kuopio, Department of
, 1996
"... In this short communication we suggest an alternative for root tracking algorithms that compute the roots explicitly. The proposed method is based on first using any preferred algorithm to track the transversal model parameters and the subsequent use of the second order perturbation expansion for th ..."
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Cited by 3 (3 self)
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In this short communication we suggest an alternative for root tracking algorithms that compute the roots explicitly. The proposed method is based on first using any preferred algorithm to track the transversal model parameters and the subsequent use of the second order perturbation expansion
CONVERGENT PERTURBATION EXPANSION FOR THE ANHARMONIC OSCILLATOR
, 1982
"... We study the ground state as well as the first three excited states of the anharmonic oscillator with anharmonicity hx 4 for a range of h = (0, 10) with the firstorder logarithmic perturbation iteration method (FOLPIM). This leads to convergent results. The initial choice of the wave function seem ..."
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is regular. For excited states where the wave functions have nodes, the zeros must be factored out before the logartihm is taken of the envelope of the wave function [24]. The logarithmic perturbation expansion has been used to restudy the?,x 4 anharmonic oscillator to 72nd
Stochastic Perturbation Theory
, 1988
"... . In this paper classical matrix perturbation theory is approached from a probabilistic point of view. The perturbed quantity is approximated by a firstorder perturbation expansion, in which the perturbation is assumed to be random. This permits the computation of statistics estimating the variatio ..."
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Cited by 907 (36 self)
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. In this paper classical matrix perturbation theory is approached from a probabilistic point of view. The perturbed quantity is approximated by a firstorder perturbation expansion, in which the perturbation is assumed to be random. This permits the computation of statistics estimating
1Computation of the coeffi cients in perturbation expansions
, 2008
"... Abstract In this note we express the coefficients of the perturbation expansion by the matrix entries of the perturbation matrix and the perturbed matrix. We also present computer programs to perform the computation of the coefficients. 1. ..."
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Abstract In this note we express the coefficients of the perturbation expansion by the matrix entries of the perturbation matrix and the perturbed matrix. We also present computer programs to perform the computation of the coefficients. 1.
Results 1  10
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4,599