Search arXivSearch

arXiv · 1412.0277

Spectral asymptotics for canonical systems

Abstract

Based on continuity properties of the de Branges correspondence, we develop a new approach to study the high-energy behavior of Weyl-Titchmarsh and spectral functions of $2\times2$ first order canonical systems. Our results improve several classical results and solve open problems posed by previous authors. Furthermore, they are applied to radial Dirac and radial Schrödinger operators as well as to Krein strings and generalized indefinite strings.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jonathan Eckhardt, Aleksey Kostenko, Gerald Teschl. 2018-04-01. Spectral asymptotics for canonical systems. https://doi.org/10.1515/crelle-2015-0034

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Critical almost Mathieu operator: hidden singularity, gap continuity, and the Hausdorff dimension of the spectrum

We obtain a representation of the critical almost Mathieu family as a Jacobi matrix that has a singularity. This allows us to prove that the Hausdorff dimension of its spectrum is not larger than 1/2 for all irrational frequencies, solving a long-standing problem. Other corollaries include two very short proofs of zero measure of the spectrum (e.g. Problem 5 in B. Simon's list of the 21'st century problems). We also obtain continuity of the measure of the spectrum for general singular Jacobi matrices, and prove a similar Hausdorff dimension result for the quantum graph graphene.

math.SP

Sharp bounds for higher mixed Steklov-Robin eigenvalues on domains with holes

This article is concerned with mixed Steklov--Robin eigenvalues on bounded domains in $\mathbb{R}^{n}, n \geq 2$, with Lipschitz boundary. Specifically, we consider domains with symmetry of order $4$ containing a spherical hole. We obtain isoperimetric inequalities for the $k$-th Steklov-Robin eigenvalues for each $k \in \{2, 3, \dots, n+1\}$. We provide examples to emphasize the fact that the symmetry assumptions, on the family of domains considered, are crucial.

math.SP

The Y-partition is the optimal three-partition for the disc and the harmonic oscillator

We prove that the Y-partition into three equal sectors is the minimal spectral three-partition both for the Dirichlet Laplacian on the unit disc and for the planar harmonic oscillator $-Δ+|x|^2$, with minimal energies $j_{3/2,1}^{2}$ and $5$; for the disc, this confirms a conjecture of Helffer and Hoffmann-Ostenhof. The minimizing regular strong partition is unique up to rotation, and every open minimizing partition has cells with the Dirichlet form domains of the sectors. The proof is a positive radial transplantation to the sphere that preserves segregation and matches the angular-energy measures of the separated model states; the three-lune theorem of Helffer, Hoffmann-Ostenhof, and Terracini then gives the lower bound. The transplantation lowers the shifted quadratic form by a nonnegative defect with strictly positive radial weight; in the equality case, spherical equipartition makes the defects vanish, which separates variables, and a Poincaré inequality on the circle identifies the sectors.

math.SP