7 papers
A fresh look at the Peierls-Onsager substitution
Horia D. Cornean, Bernard Helffer, Radu Purice
We formulate a general version of the Peierls-Onsager substitution for a finite family of Bloch eigenvalues under a local spectral gap hypothesis, via strongly localized tight-fram…
On the magnetic Dirichlet to Neumann operator on the exterior of the disk -- diamagnetism, weak-magnetic field limit and flux effects
Helffer Bernard, Nicoleau Francois
In this paper, we analyze the magnetic Dirichlet-to-Neumann operator (D-to-N map) on the exterior of the disk with respect to a magnetic potential $A_{b, ν}=A^b + A…
Asymptotics for the magnetic Dirichlet-to-Neumann eigenvalues in general domains
Bernard Helffer, Ayman Kachmar, Francois Nicoleau
Inspired by a paper by T. Chakradhar, K. Gittins, G. Habib and N. Peyerimhoff, we analyze their conjecture that the ground state energy of the magnetic Dirichlet-to-Neumann operato…
Inequalities between Dirichlet and Neumann eigenvalues on Carnot groups
Rupert L. Frank, Bernard Helffer, Ari Laptev
We show that the -th Dirichlet eigenvalue of the sub-Laplacian on an open set of a Carnot group is greater than the -st Neumann eigenvalue. This extends earlier results i…
On the magnetic Dirichlet to Neumann operator on the disk -- strong diamagnetism and strong magnetic field limit--
Helffer Bernard, Nicoleau François
Inspired by a paper by T. Chakradhar, K. Gittins, G. Habib and N. Peyerimhoff, we analyze their conjecture that the ground state energy of the magnetic Dirichlet-to-Neumann operato…
A rigorous Peierls-Onsager effective dynamics for semimetals in long-range magnetic fields
Horia D. Cornean, Bernard Helffer, Radu Purice
We consider periodic (pseudo)differential {elliptic operators of Schrödinger type} perturbed by weak magnetic fields not vanishing at infinity, and extend our previous analysis in…