Results 71 to 80 of about 147,544 (216)

Spectral perturbation bounds for selfadjoint operators [PDF]

open access: yesarXiv, 2007
We give general spectral and eigenvalue perturbation bounds for a selfadjoint operator perturbed in the sense of the pseudo-Friedrichs extension. We also give several generalisations of the aforementioned extension. The spectral bounds for finite eigenvalues are obtained by using analyticity and monotonicity properties (rather than variational ...
arxiv  

Some inequalities for generalized eigenvalues of perturbation problems on Hermitian matrices

open access: yesJournal of Inequalities and Applications, 2018
In the paper, the authors establish some inequalities for generalized eigenvalues of perturbation problems on Hermitian matrices and modify shortcomings of some known inequalities for generalized eigenvalues in the related literature.
Yan Hong, Dongkyu Lim, Feng Qi
doaj   +1 more source

Asymptotic expansion for the eigenvalues of a perturbed anharmonic oscillator [PDF]

open access: yesarXiv, 2019
In this article, we study the spectral properties of the perturbation of the generalized anharmonic oscillator. We consider a piecewise H\"older continuous perturbation and investigate how the H\"older constant can affect the eigenvalues. More precisely, we derive several first terms in the asymptotic expansion for the eigenvalues.
arxiv  

Threshold Effects for the Generalized Friedrichs Model with the Perturbation of Rank One

open access: yesAbstract and Applied Analysis, 2012
A family Hμ(p), μ>0, p∈𝕋2 of the Friedrichs models with the perturbation of rank one, associated to a system of two particles, moving on the two-dimensional lattice ℤ2 is considered. The existence or absence of the unique eigenvalue of the operator Hμ(p)
Saidakhmat Lakaev   +2 more
doaj   +1 more source

Pairs of positive solutions for resonant singular equations with the p-Laplacian

open access: yesElectronic Journal of Differential Equations, 2017
We consider a nonlinear elliptic equation driven by the Dirichlet p-Laplacian with a singular term and a (p-1)-linear perturbation which is resonant at $+\infty$ with respect to the principal eigenvalue. Using variational tools, together with suitable
Nikolaos S. Papageorgiou   +2 more
doaj  

Multiple-rank modification of symmetric eigenvalue problem

open access: yesMethodsX, 2018
Rank-1 modifications applied k-times (k > 1) often are performed to achieve a rank-k modification. We propose a rank- k modification for enhancing computational efficiency. As the first step toward a rank- k modification, an algorithm to perform a rank-2
HyungSeon Oh, Zhe Hu
doaj  

A Simple Matrix Approach to Determination of the Helium Atom Energies

open access: yesJurnal Penelitian Fisika dan Aplikasinya, 2019
Calculation of He atomic energy levels using the first order perturbation theory taught in the Basic Quantum Mechanics course has led to relatively large errors.
Redi Kristian Pingak   +2 more
doaj   +1 more source

A trace formula and high energy spectral asymptotics for the perturbed Landau Hamiltonian [PDF]

open access: yesarXiv, 2003
A two-dimensional Schr\"odinger operator with a constant magnetic field perturbed by a smooth compactly supported potential is considered. The spectrum of this operator consists of eigenvalues which accumulate to the Landau levels. We call the set of eigenvalues near the $n$'th Landau level an $n$'th eigenvalue cluster, and study the distribution of ...
arxiv  

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