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Related papers: Non-real Eigenvalues for PT-Symmetric Double Wells

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The condition of self-adjointness ensures that the eigenvalues of a Hamiltonian are real and bounded below. Replacing this condition by the weaker condition of ${\cal PT}$ symmetry, one obtains new infinite classes of complex Hamiltonians…

Mathematical Physics · Physics 2009-10-30 Carl M. Bender , Stefan Boettcher

The work is devoted to the study of the similarity of a correct restriction to some self-adjoint operator in the case when the minimal operator is symmetric. The resulting theorem was applied to the Sturm-Liouville operator and the Laplace…

Spectral Theory · Mathematics 2021-02-02 B. N. Biyarov , Z. A. Zakarieva , G. K. Abdrasheva

We study the distribution of eigenvalues for selfadjoint $h$--pseudodifferential operators in dimension two, arising as perturbations of selfadjoint operators with a periodic classical flow. When the strength $\varepsilon$ of the…

Spectral Theory · Mathematics 2014-01-16 Michael A. Hall , Michael Hitrik , Johannes Sjoestrand

In this paper, we give Lieb-Thirring type inequalities for isolated eigenvalues of $d$-dimensional non-selfadjoint Schr\"{o}dinger operators with complex-valued and dilation analytic potentials. In order to derive them, we prove that…

Spectral Theory · Mathematics 2019-06-20 Norihiro Someyama

This article is devoted to the spectral analysis of the electro-magnetic Schr\"odinger operator on the Euclidean plane. In the semiclassical limit, we derive a pseudo-differential effective operator that allows us to describe the spectrum…

Spectral Theory · Mathematics 2022-01-26 Léo Morin , Nicolas Raymond , San Vu Ngoc

The particle in a well in dimension one is a classical problem in quantum mechanics. We study higher-dimensional analogues of the problem, where the well is a smooth domain in $\mathbb{R}^d$. We show that simple eigenvalues and…

Analysis of PDEs · Mathematics 2025-08-20 Peter Hintz , Aaron Moser

Using purely physical arguments it is claimed that for ID Schrodinger operators with complex PT- Symmatric potentials having a purely real attractive potential well and a purely imaginary repulsive part,bound state eigenvalues will be…

Quantum Physics · Physics 2007-05-23 S. Banerjee , R. Roychoudhury

We analyse some PT-symmetric oscillators with $T_{d}$ symmetry that depend on a potential parameter $g$. We calculate the eigenvalues and eigenfunctions for each irreducible representation and for a range of values of $g$. Pairs of…

Quantum Physics · Physics 2015-06-22 Paolo Amore , Francisco M. Fernández , Javier Garcia

We discuss a PT-symmetric Hamiltonian with complex eigenvalues. It is based on the dimensionless Schr\"{o}dinger equation for a particle in a square box with the PT-symmetric potential $V(x,y)=iaxy$. Perturbation theory clearly shows that…

Quantum Physics · Physics 2015-06-17 Francisco M Fernández , Javier Garcia

We consider non-selfadjoint perturbations of a self-adjoint $h$-pseudodifferential operator in dimension 2. In the present work we treat the case when the classical flow of the unperturbed part is periodic and the strength $\epsilon $ of…

Spectral Theory · Mathematics 2007-05-23 Johannes Sjoestrand

In this work we extend a previous work about the Weyl asymptotics of the distribution of eigenvalues of non-self-adjoint differential operators with small multiplicative random perturbations, by treating the case of operators on compact…

Spectral Theory · Mathematics 2008-09-25 Johannes Sjoestrand

We show that the quasi-exactly solvable eigenvalues of the Schr\"odinger equation for the PT-invariant potential $V(x) = -(\zeta \cosh 2x -iM)^2$ are complex conjugate pairs in case the parameter M is an even integer while they are real in…

Quantum Physics · Physics 2009-11-06 Avinash Khare , Bhabani Prasad Mandal

We prove quantitative bounds on the eigenvalues of non-selfadjoint unbounded operators obtained from selfadjoint operators by a perturbation that is relatively-Schatten. These bounds are applied to obtain new results on the distribution of…

Spectral Theory · Mathematics 2009-09-10 Michael Demuth , Marcel Hansmann , Guy Katriel

For relatively form-compact perturbations of non-negative selfadjoint operators, we obtain an upper bound on the number of discrete eigenvalues in half-planes separated from the positive real axis. The bound is given in terms of a partial…

Spectral Theory · Mathematics 2026-03-25 Sabine Bögli , Sukrid Petpradittha

A standard perturbation result states that perturbed eigenvalues and eigenprojections admit a perturbation series provided that the operator norm of the perturbation is smaller than a constant times the corresponding eigenvalue isolation…

Functional Analysis · Mathematics 2019-10-21 Martin Wahl

We obtain necessary and sufficient conditions for emerging of small eigenvalue for Schr\"odinger operator on plane under local operator perturbations. In the case the eigenvalue emerges we construct its asymptotics. The examples are given.

Mathematical Physics · Physics 2007-05-23 R. R. Gadyl'shin

The central problem we consider is the distribution of eigenvalues of closed linear operators which are not selfadjoint, with a focus on those operators which are obtained as perturbations of selfadjoint linear operators. Two methods are…

Spectral Theory · Mathematics 2014-03-25 Michael Demuth , Marcel Hansmann , Guy Katriel

The goal of the paper is to investigate the dynamics of the eigenvalues of the Sturm-Liouville operator with summable PT-symmetric potential on the finite interval. It turns out that the case of a complex Airy operator presents an exactly…

Spectral Theory · Mathematics 2017-07-27 A. A. Shkalikov , S. N. Tumanov

In many PT symmetric models with real spectra, apparently, energy levels "merge and disappear" at a point of the spontaneous PT-symmetry breaking. We argue that such an oversimplified and discontinuous physical interpretation of this…

High Energy Physics - Theory · Physics 2014-11-18 Miloslav Znojil , Geza Levai

We show that at least the quasi-exactly solvable eigenvalues of the Schr\"odinger equation with the potential $V(x) = -(\zeta \cosh 2x -iM)^2$ as well as the periodic potential $V(x) = (\zeta \cos 2\theta -iM)^2$ are real for the…

Quantum Physics · Physics 2007-05-23 Avinash Khare , Bhabani Prasad Mandal