scholarly journals Some notes on conformable fractional Sturm–Liouville problems

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Wei-Chuan Wang
Keyword(s):  
Asymptotic Expansion ◽  
Eigenvalue Problem ◽  
Efficient Method ◽  
Sturm Liouville

AbstractThe conformable fractional eigenvalue problem $$\begin{aligned} -D_{x}^{\alpha }D_{x}^{\alpha }y+q(x)y=\lambda \rho (x)y \end{aligned}$$ − D x α D x α y + q ( x ) y = λ ρ ( x ) y is considered. We employ an easy and efficient method to derive its eigenvalue asymptotic expansion. On the basis of this result, we also investigate Ambarzumyan problems related to this eigenvalue problem as an application.

Asymptotics of Sturm-Liouville eigenvalues for problems on a finite interval with one limit-circle singularity, I

1984 ◽  
Vol 99 (1-2) ◽  
pp. 51-70 ◽  
Author(s):  
F. V. Atkinson ◽  
C. T. Fulton
Keyword(s):  
Asymptotic Expansion ◽  
Eigenvalue Problem ◽  
Hypergeometric Function ◽  
Finite Interval ◽  
Confluent Hypergeometric Function ◽  
Limit Circle ◽  
Asymptotic Formulae ◽  
Sturm Liouville

SynopsisAsymptotic formulae for the positive eigenvalues of a limit-circle eigenvalue problem for –y” + qy = λy on the finite interval (0, b] are obtained for potentials q which are limit circle and non-oscillatory at x = 0, under the assumption xq(x)∈L1(0,6). Potentials of the form q(x) = C/xk, 0<fc<2, are included. In the case where k = 1, an independent check based on the limit-circle theory of Fulton and an asymptotic expansion of the confluent hypergeometric function, M(a, b; z), verifies the main result.

scholarly journals Oscillating behaviour of the spectrum for a plasmonic problem in a domain with a rounded corner

2018 ◽  
Vol 52 (4) ◽  
pp. 1285-1313 ◽  
Author(s):  
Lucas Chesnel ◽  
Xavier Claeys ◽  
Sergei A. Nazarov
Keyword(s):  
Asymptotic Expansion ◽  
Eigenvalue Problem ◽  
Recent Work ◽  
Present Article ◽  
Error Estimates ◽  
Numerical Experiments ◽  
Source Term ◽  
Oscillatory Behaviour ◽  
Time Harmonic ◽  
Rounded Corner

We investigate the eigenvalue problem −div(σ∇u) = λu (P) in a 2D domain Ω divided into two regions Ω±. We are interested in situations where σ takes positive values on Ω+ and negative ones on Ω−. Such problems appear in time harmonic electromagnetics in the modeling of plasmonic technologies. In a recent work [L. Chesnel, X. Claeys and S.A. Nazarov, Asymp. Anal. 88 (2014) 43–74], we highlighted an unusual instability phenomenon for the source term problem associated with (P): for certain configurations, when the interface between the subdomains Ω± presents a rounded corner, the solution may depend critically on the value of the rounding parameter. In the present article, we explain this property studying the eigenvalue problem (P). We provide an asymptotic expansion of the eigenvalues and prove error estimates. We establish an oscillatory behaviour of the eigenvalues as the rounding parameter of the corner tends to zero. We end the paper illustrating this phenomenon with numerical experiments.

scholarly journals Boundary values for an eigenvalue problem with a singular potential

2017 ◽  
Vol 7 (3) ◽  
pp. 293-300
Author(s):  
Münevver Tuz
Keyword(s):  
Eigenvalue Problem ◽  
Liouville Equation ◽  
Singular Potential ◽  
Inverse Spectral Problem ◽  
Three Dimensional ◽  
Boundary Values ◽  
Symmetric Potential ◽  
Sturm Liouville ◽  
The Difference ◽  
New Evidence

In this paper we consider the inverse spectral problem on the interval [0,1]. This determines the three-dimensional Schrödinger equation with from singular symmetric potential. We show that the two spectrums uniquely identify the potential function q(r) in a single Sturm-Liouville equation, and we obtain new evidence for the difference in the q(r)-q(r)of the Hochstadt theorem.

High frequency asymptotic analysis of a string with rapidly oscillating density

2000 ◽  
Vol 11 (6) ◽  
pp. 595-622 ◽  
Author(s):  
C. CASTRO ◽  
E. ZUAZUA
Keyword(s):  
Asymptotic Expansion ◽  
Eigenvalue Problem ◽  
Asymptotic Analysis ◽  
Explicit Formula ◽  
High Frequency ◽  
Critical Size ◽  
The Other ◽  
Full Description ◽  
Eigenvalues And Eigenfunctions ◽  
Asymptotic Formulae

We consider the eigenvalue problem associated with the vibrations of a string with rapidly oscillating periodic density. In a previous paper we stated asymptotic formulae for the eigenvalues and eigenfunctions when the size of the microstructure ε is shorter than the wavelength of the eigenfunctions 1/√λε. On the other hand, it has been observed that when the size of the microstructure is of the order of the wavelength of the eigenfunctions (ε ∼ 1/√λε) singular phenomena may occur. In this paper we study the behaviour of the eigenvalues and eigenfunctions when 1/√λε is larger than the critical size ε. We use the WKB approximation which allows us to find an explicit formula for eigenvalues and eigenfunctions with respect to ε. Our analysis provides all order correction formulae for the limit eigenvalues and eigenfunctions above the critical size. Each term of the asymptotic expansion requires one more derivative of the density. Thus, a full description requires the density to be C∞ smooth.

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