Weyl asymptotics for perturbed functional difference operators

We consider the difference operator HW = U + U−1 + W, where U is the self-adjoint Weyl operator U = e−bP, b > 0, and the potential W is of the form W(x) = x2N + r(x) with N∈ℕ and |r(x)| ≤ C(1 + |x|2N−ɛ) for some 0 < ɛ ≤ 2N − 1. This class of potentials W includes polynomials of even degree wit...

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Bibliographic Details
Published in:Journal of Mathematical Physics
Main Authors: Laptev, Ari, Schimmer, Lukas, Takhtajan, Leon A.
Format: Article in Journal/Newspaper
Language:English
Published: 2019
Subjects:
Online Access:https://curis.ku.dk/portal/da/publications/weyl-asymptotics-for-perturbed-functional-difference-operators(7fc1d85b-7651-4db6-b158-e1268b86f4e3).html
https://doi.org/10.1063/1.5093401
https://curis.ku.dk/ws/files/244238829/OA_Weyl_asymptotics_for_perturbed_functional_difference_operators.pdf
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Summary:We consider the difference operator HW = U + U−1 + W, where U is the self-adjoint Weyl operator U = e−bP, b > 0, and the potential W is of the form W(x) = x2N + r(x) with N∈ℕ and |r(x)| ≤ C(1 + |x|2N−ɛ) for some 0 < ɛ ≤ 2N − 1. This class of potentials W includes polynomials of even degree with leading coefficient 1, which have recently been considered in Grassi and Mariño [SIGMA Symmetry Integrability Geom. Methods Appl. 15, 025 (2019)]. In this paper, we show that such operators have discrete spectrum and obtain Weyl-type asymptotics for the Riesz means and for the number of eigenvalues. This is an extension of the result previously obtained in Laptev et al. [Geom. Funct. Anal. 26, 288–305 (2016)] for W = V + ζV−1, where V = e2πbx, ζ > 0