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4,599
Convergence Behavior of Variational Perturbation Expansions
, 1996
"... Variational weakcoupling perturbation theory yields converging approximations, uniformly in the coupling strength. This allows us to calculate directly the coefficients of strongcoupling expansions. For the anharmonic oscillator we explain the physical origin of the empirically observed convergenc ..."
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Variational weakcoupling perturbation theory yields converging approximations, uniformly in the coupling strength. This allows us to calculate directly the coefficients of strongcoupling expansions. For the anharmonic oscillator we explain the physical origin of the empirically observed
Perturbative Expansion of the ChernSimons Integral
"... The necessity of the asymptotic expansion in infinite dimensions arises from the pioneering work of the ChernSimons theory by Witten [10] in 1989. However, the exponentia13rd term of the ChernSimons theory is less likely to be handled by techniques known at present, so that we will challenge a new ..."
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The necessity of the asymptotic expansion in infinite dimensions arises from the pioneering work of the ChernSimons theory by Witten [10] in 1989. However, the exponentia13rd term of the ChernSimons theory is less likely to be handled by techniques known at present, so that we will challenge a
Convergence of Perturbation Expansions in Fermionic Models
, 2002
"... Abstract. An estimate on the operator norm of an abstract fermionic renormalization group map is derived. This abstract estimate is applied in another paper to construct the thermodynamic Green’s functions of a two dimensional, weakly coupled fermion gas with an asymmetric Fermi curve. The estimate ..."
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Abstract. An estimate on the operator norm of an abstract fermionic renormalization group map is derived. This abstract estimate is applied in another paper to construct the thermodynamic Green’s functions of a two dimensional, weakly coupled fermion gas with an asymmetric Fermi curve. The estimate derived here is strong enough to control everything but the sum of all quartic contributions to the Green’s functions.
Cumulants in Perturbation Expansions for NonEquilibrium Field Theory
"... The formulation of perturbation expansions for a quantum field theory of strongly interacting systems in a general nonequilibrium state is discussed. Nonvanishing initial correlations are included in the formulation of the perturbation expansion in terms of cumulants. The cumulants are shown to be ..."
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The formulation of perturbation expansions for a quantum field theory of strongly interacting systems in a general nonequilibrium state is discussed. Nonvanishing initial correlations are included in the formulation of the perturbation expansion in terms of cumulants. The cumulants are shown
Another Perturbative Expansion in N on abelian Gauge Theory
, 1993
"... We consider a new perturbation scheme in nonabelian gauge theory. Pure YangMills theory in three dimensions is taken as a concrete example. The zerothorder in the perturbative expansion is given by BF theory coupled to a Sttickelberglike field. The effective coupling for the expansion can be smal ..."
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We consider a new perturbation scheme in nonabelian gauge theory. Pure YangMills theory in three dimensions is taken as a concrete example. The zerothorder in the perturbative expansion is given by BF theory coupled to a Sttickelberglike field. The effective coupling for the expansion can
A Complete Perturbative Expansion for Constrained Quantum Dynamics
, 1994
"... A complete perturbative expansion for the Hamiltonian describing the motion of a quantomechanical system constrained to move on an The quantomechanical description of constrained systems is extremely important in physics and since the early days of quantum mechanics several techniques have been deve ..."
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A complete perturbative expansion for the Hamiltonian describing the motion of a quantomechanical system constrained to move on an The quantomechanical description of constrained systems is extremely important in physics and since the early days of quantum mechanics several techniques have been
Perturbation expansions of signal subspaces for long signals
 Statistics and Its Interface
, 2010
"... Singular Spectrum Analysis and many other subspacebased methods of signal processing are implicitly relying on the assumption of close proximity of unperturbed and perturbed signal subspaces extracted by the Singular Value Decomposition of special “signal ” and “perturbed signal” matrices. In this ..."
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. In this paper, the analysis of the largest principal angle between these subspaces is performed in terms of the perturbation expansions of the corresponding orthogonal projectors. Applicable upper bounds are derived. The main attention is paid to the asymptotic case when the length of the time series tends
Results 11  20
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4,599