65 citations · 165 across the 14 of their papers we have counts for
9 papers · 1 filter
The second Weyl coefficient for a first order system
Zhirayr Avetisyan, Johannes Sjoestrand, Dmitri Vassiliev
For a scalar elliptic self-adjoint operator on a compact manifold without boundary we have two-term asymptotics for the number of eigenvalues between zero and lambda when lambda te…
Large bi-diagonal matrices and random perturbations
Johannes Sjoestrand, Martin Vogel
This is a first paper by the authors dedicated to the distribution of eigenvalues for random perturbations of large bidiagonal Toeplitz matrices.
Non-real Eigenvalues for PT-Symmetric Double Wells
Amina Benbernou, Naima Boussekkine, Nawal Mecherout +2
We study small, PT-symmetric perturbations of self-adjoint double-well Schrödinger operators in dimension . We prove that the eigenvalues stay real for a very small pertur…
Interior eigenvalue density of Jordan matrices with random perturbations
Johannes Sjoestrand, Martin Vogel
We study the eigenvalue distribution of a large Jordan block subject to a small random Gaussian perturbation. A result by E.B. Davies and M. Hager shows that as the dimension of th…
Spectra for semiclassical operators with periodic bicharacteristics in dimension two
Michael A. Hall, Michael Hitrik, Johannes Sjoestrand
We study the distribution of eigenvalues for selfadjoint --pseudodifferential operators in dimension two, arising as perturbations of selfadjoint operators with a periodic class…
Resolvent estimates for elliptic quadratic differential operators
Michael Hitrik, Johannes Sjoestrand, Joe Viola
Sharp resolvent bounds for non-selfadjoint semiclassical elliptic quadratic differential operators are established, in the interior of the range of the associated quadratic symbol.
Tunnel effect and symmetries for Kramers Fokker-Planck type operators
Frederic Herau, Michael Hitrik, Johannes Sjoestrand
We study operators of Kramers-Fokker-Planck type in the semiclassical limit, assuming that the exponent of the associated Maxwellian is a Morse function with a finite number …
Eigenvalue distribution for non-self-adjoint operators with small multiplicative random perturbations
Johannes Sjoestrand
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…
Non-selfadjoint perturbations of selfadjoint operators in 2 dimensions I
Michael Hitrik, Johannes Sjoestrand
This is the first in a series of works devoted to small non-selfadjoint perturbations of selfadjoint -pseudodifferential operators in dimension 2. In the present work we treat t…