From the 1 of 13 linked papers with an AI index.
13 papers
A Local-to-Global Propagation Principle for Dirichlet-to-Neumann Maps
Thierry Daudé, Alberto Enciso, Bernard Helffer +2
The paper proves several local‑to‑global propagation results showing that equality of Dirichlet‑to‑Neumann maps on a small part of the boundary forces equality on the whole boundar…
Pleijel's theorem for a class of degenerate elliptic operators
Rupert L. Frank, Bernard Helffer
We prove an asymptotic upper bound on the number of nodal domains of eigenfunctions of a class of degenerate elliptic operators. Our proof yields the same constant as in Pleijel's…
The fibre operators in the Bloch-Floquet decomposition of periodic magnetic pseudo-differential operators
Horia D. Cornean, Bernard Helffer, Radu Purice
We study the structure of the fibre operators corresponding to periodic magnetic pseudo-differential operators having periodic magnetic potentials. We obtain explicit formulas for…
A Sharp Regularity Threshold for Uniqueness in Riemannian Calderón-type Problems
Thierry Daudé, Alberto Enciso, Bernard Helffer +2
We prove a sharp regularity threshold for uniqueness in two anisotropic Calderón-type inverse problems in dimension . The main setting is the Riemannian Schrödinger probl…
Flux effects on Magnetic Laplace and Steklov eigenvalues in the exterior of a disk
Bernard Helffer, Ayman Kachmar, François Nicoleau
We derive a three-term asymptotic expansion for the lowest eigenvalue of the magnetic Laplace and Steklov operators in the exterior of the unit disk in the strong magnetic field li…
On uniqueness of radial potentials for given Dirichlet spectra with distinct angular momenta
Damien Gobin, Benoît Grébert, Bernard Helffer +1
We consider an inverse spectral problem for radial Schrödinger operators with singular potentials. First, we show that the knowledge of the Dirichlet spectra for infinitely many a…