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This paper is devoted to providing quantitative bounds on the location of eigenvalues, both discrete and embedded, of non self-adjoint Lam\'e operators of elasticity $-\Delta^\ast + V$ in terms of suitable norms of the potential $V$. In…

Spectral Theory · Mathematics 2021-01-26 Biagio Cassano , Lucrezia Cossetti , Luca Fanelli

We study sub-Dirac operators that are associated with left-invariant bracket-generating sub-Riemannian structures on compact quotients of nilpotent semi-direct products $G=\mathbb{R}^n\rtimes_A\mathbb{R}$. We will prove that these operators…

Spectral Theory · Mathematics 2013-11-12 Ines Kath , Oliver Ungermann

We prove that canonical Dirac expression with linear potential generates operators on axis and half axis, for which we can find the eigenvalues and eigenfunctions in explicit form. We construct the perturbations of these operators with in…

Spectral Theory · Mathematics 2016-09-01 Yuri A. Ashrafyan , Tigran N. Harutyunyan

We show that the eigenvalues of the intrinsic Dirac operator on the boundary of a Euclidean domain can be obtained as the limits of eigenvalues of Euclidean Dirac operators, either in the domain with a MIT-bag type boundary condition or in…

Mathematical Physics · Physics 2020-06-23 Andrei Moroianu , Thomas Ourmières-Bonafos , Konstantin Pankrashkin

We get optimal lower bounds for the eigenvalues of the submanifold Dirac operator on locally reducible Riemannian manifolds in terms of intrinsic and extrinsic expressions. The limiting-cases are also studied. As a corollary, one gets…

Differential Geometry · Mathematics 2020-10-27 Yongfa Chen

Under various elliptic boundary conditions, we obtain lower eigenvalue estimates for Dirac operators by using Hormander's weighted $L^2$-technique. Lower bounds in terms of the volume of the underlying manifolds are also deduced from the…

Differential Geometry · Mathematics 2019-07-16 Qingchun Ji , Li Lin

Depending on the behaviour of the complex-valued electromagnetic potential in the neighbourhood of infinity, pseudomodes of one-dimensional Dirac operators corresponding to large pseudoeigenvalues are constructed. This is a first systematic…

Mathematical Physics · Physics 2022-08-22 David Krejcirik , Tho Nguyen Duc

We consider an elliptic self-adjoint first order differential operator acting on pairs (2-columns) of complex-valued half-densities over a connected compact 3-dimensional manifold without boundary. The principal symbol of our operator is…

Spectral Theory · Mathematics 2015-05-05 Olga Chervova , Robert J. Downes , Dmitri Vassiliev

We exploit the connection between quantum dot Dirac operators and $\overline\partial$-Robin Laplacians. First, we find a graphical relation between their smallest positive eigenvalues, which allows us to deduce a recipe for translating…

Analysis of PDEs · Mathematics 2026-05-29 Joaquim Duran

The relative distance between eigenvalues of the compression of a not necessarily semibounded self-adjoint operator to a closed subspace and some of the eigenvalues of the original operator in a gap of the essential spectrum is considered.…

Spectral Theory · Mathematics 2024-07-23 Albrecht Seelmann

For a compact spin manifold $M$ isometrically embedded into Euclidean space, we derive the extrinsic estimates from above and below for eigenvalues of the Dirac operators, which depend on the second fundamental form of the embedding. We…

Differential Geometry · Mathematics 2007-05-23 Daguang Chen

We study eigenvalues of the Dirac operator with canonical form \begin{equation} L_{p,q} \begin{pmatrix} u \\ v \end{pmatrix}= \begin{pmatrix} 0 & -1 \\ 1 & 0 \end{pmatrix}\frac{d}{dt} \begin{pmatrix} u \\ v \end{pmatrix}+\begin{pmatrix} -p…

Spectral Theory · Mathematics 2023-12-27 Vishwam Khapre , Kang Lyu , Andrew Yu

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

In this work, we develop the method of multipliers for electromagnetic Dirac operators and establish sufficient conditions on the magnetic and electric fields that guarantee the absence of point spectrum. In the massless case, our approach…

Spectral Theory · Mathematics 2025-12-17 Naiara Arrizabalaga , Lucrezia Cossetti , Matias Morales

In the presence of a non-vanishing chemical potential the eigenvalues of the Dirac operator become complex. We use a random matrix model approach to calculate analytically all correlation functions at weak and strong non-Hermiticity for…

High Energy Physics - Lattice · Physics 2007-05-23 G. Akemann

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

In this note, we prove lower and upper bounds for Dirac operators of submanifolds in certain ambient manifolds in terms of conformal and extrinsic quantities.

Differential Geometry · Mathematics 2018-10-18 Qun Chen , Linlin Sun

We consider the Dirac operator on compact quaternionic Kaehler manifolds and prove a lower bound for the spectrum. This estimate is sharp since it is the first eigenvalue of the Dirac operator on the quaternionic projective space.

dg-ga · Mathematics 2008-02-03 W. Kramer , U. Semmelmann , G. Weingart

Considering different self-adjoint realisations of positively projected massless Coulomb-Dirac operators we find out, under which conditions any negative perturbation, however small, leads to emergence of negative spectrum. We also prove…

Mathematical Physics · Physics 2018-03-28 Sergey Morozov , David Müller

For a class of non-selfadjoint semiclassical pseudodifferential operators with double characteristics, we study bounds for resolvents and estimates for low lying eigenvalues. Specifically, assuming that the quadratic approximations of the…

Analysis of PDEs · Mathematics 2009-02-23 Michael Hitrik , Karel Pravda-Starov