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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

This is the second in a series of works devoted to small non-selfadjoint perturbations of selfadjoint semiclassical pseudodifferential operators in dimension 2. As in our previous work, we consider the case when the classical flow of the…

Spectral Theory · Mathematics 2007-05-23 Michael Hitrik , Johannes Sjoestrand

This is the third in a series of works devoted to spectral asymptotics for non-selfadjoint perturbations of selfadjoint $h$-pseudodifferential operators in dimension 2. We assume that the unperturbed operator has a periodic Hamilton flow,…

Spectral Theory · Mathematics 2007-05-23 M. Hitrik , J. Sjoestrand

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

We study spectral asymptotics for small non-selfadjoint perturbations of selfadjoint $h$-pseudodifferential operators in dimension 2, assuming that the classical flow of the unperturbed part possesses several invariant Lagrangian tori…

Spectral Theory · Mathematics 2007-05-23 Michael Hitrik , Johannes Sjoestrand , San Vu Ngoc

We study semiclassical asymptotics for spectra of non-selfadjoint perturbations of selfadjoint analytic $h$-pseudodifferential operators in dimension 2, assuming that the classical flow of the unperturbed part is completely integrable.…

Spectral Theory · Mathematics 2015-02-24 Michael Hitrik , Johannes Sjoestrand

We study spectral asymptotics and resolvent bounds for non-selfadjoint perturbations of selfadjoint $h$-pseudodifferential operators in dimension 2, assuming that the classical flow of the unperturbed part is completely integrable. Spectral…

Spectral Theory · Mathematics 2007-05-23 Michael Hitrik , Johannes Sjoestrand

We consider a non-selfadjoint $h$-differential model operator $P_h$ in the semiclassical limit ($h\rightarrow 0$) subject to random perturbations with a small coupling constant $\delta$. Assume that $\exp(-\frac{1}{Ch}) < \delta \ll…

Spectral Theory · Mathematics 2016-09-27 Martin Vogel

We consider quite general $h$-pseudodifferential operators on $R^n$ with small random perturbations and show that in the limit of small $h$ the eigenvalues are distributed according to a Weyl law with a probabality that tends to 1. The…

Spectral Theory · Mathematics 2007-05-23 Mildred Hager , Johannes Sjoestrand

We consider nonsymmetric rank one singular perturbations of a selfadjoint operator, i.e., an expression of the form $\tilde A = A + \alpha\left\langle\cdot, \omega_1\right\rangle\omega_2$, $\omega_1\not = \omega_2$, $\alpha\in{\mathbb C}$,…

Functional Analysis · Mathematics 2016-08-26 Mykola Dudkin , Tetiana Vdovenko

Let $H_0$ be a purely absolutely continuous selfadjoint operator acting on some separable infinite-dimensional Hilbert space and $V$ be a compact non-selfadjoint perturbation. We relate the regularity properties of $V$ to various spectral…

Spectral Theory · Mathematics 2020-05-22 Olivier Bourget , Diomba Sambou , Amal Taarabt

We investigate the behaviour of the eigenvalues of two-dimensional Pauli operators with nonconstant magnetic fields perturbed by a sign-indefinite decaying electric potential V. We prove new eigenvalues asymptotics.

Mathematical Physics · Physics 2017-05-17 Diomba Sambou , Amal Taarabt

In this work we continue the study of the Weyl asymptotics of the distribution of eigenvalues of non-self-adjoint (pseudo)differential operators with small random perturbations, by treating the case of multiplicative perturbations in…

Spectral Theory · Mathematics 2009-12-02 Johannes Sjoestrand

The purpose of this note is to review some recent results concerning the pseudospectra and the eigenvalues asymptotics of non-selfadjoint semiclassical pseudo-differential operators subject to small random perturbations.

Spectral Theory · Mathematics 2024-10-08 Martin Vogel

We build a combinatorial invariant, called the spectral monodromy from the spectrum of a non-selfadjoint h -pseudodifferential operator with two degrees of freedom in the semi-classical limit. We treat small non-selfadjoint perturbation of…

Mathematical Physics · Physics 2014-08-05 Quang Sang Phan

In this paper, we give a description of the spectrum of a class of non-selfadjoint perturbations of selfadjoint operators in dimension one and we show that it is given by Bohr-Sommerfeld quantization conditions. To achieve this, we make use…

Spectral Theory · Mathematics 2015-11-20 Ophélie Rouby

We consider a class of one-dimensional nonselfadjoint semiclassical pseudo-differential operators, subject to small random perturbations, and study the statistical properties of their (discrete) spectra, in the semiclassical limit $h\to 0$.…

Spectral Theory · Mathematics 2022-01-19 Stéphane Nonnenmacher , Martin Vogel

We consider a non-selfadjoint $h$-differential model operator $P_h$ in the semiclassical limit ($h\rightarrow 0$) subject to small random perturbations. Furthermore, we let the coupling constant $\delta$ be $\exp\{-\frac{1}{Ch}\}\leq \delta…

Spectral Theory · Mathematics 2015-12-22 Martin Vogel

We consider two-point non-self-adjoint boundary eigenvalue problems for linear matrix differential operators. The coefficient matrices in the differential expressions and the matrix boundary conditions are assumed to depend analytically on…

Mathematical Physics · Physics 2010-04-20 Oleg N. Kirillov

We study small, PT-symmetric perturbations of self-adjoint double-well Schr\"odinger operators in dimension $n\geq 1$. We prove that the eigenvalues stay real for a very small perturbation, then bifurcate to the complex plane as the…

Spectral Theory · Mathematics 2016-06-22 Amina Benbernou , Naima Boussekkine , Nawal Mecherout , Thierry Ramond , Johannes Sjoestrand
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