Søren Fournais

Spectral methods in surface superconductivity

Preface.- Notation.- Part I Linear Analysis.- 1 Spectral Analysis of Schr..odinger Operators.- 2 Diamagnetism.- 3 Models in One Dimension.- 4 Constant Field Models in Dimension 2: Noncompact Case.- 5 Constant Field Models in Dimension 2: Discs and Their Complements.- 6 Models in Dimension 3: R3 or R3,+.- 7 Introduction to Semiclassical Methods for the Schr..odinger Operator with a Large Electric Potential.- 8 Large Field Asymptotics of the Magnetic Schr..odinger Operator: The Case of Dimension 2.- 9 Main Results for Large Magnetic Fields in Dimension 3.- Part II Nonlinear Analysis.-10 The Ginzburg-Landau Functional.- 11 Optimal Elliptic Estimates.- 12 Decay Estimates.- 13 On the Third Critical Field HC3.- 14 Between HC2 and HC3 in Two Dimensions.- 15 On the Problems with Corners.- 16 On Other Models in Superconductivity and Open Problems.- A Min-Max Principle.- B Essential Spectrum and Perssons Theorem.- C Analytic Perturbation Theory.- D About the Curl-Div System.- E Regularity Theorems and Precise Estimates in Elliptic PDE.- F Boundary Coordinates.- References.- Index.

Sharp Regularity Results for Coulombic Many-Electron Wave Functions

We show that electronic wave functions ψ of atoms and molecules have a representation ψ=ϕ, where is an explicit universal factor, locally Lipschitz, and independent of the eigenvalue and the solution ψ itself, and ϕ has second derivatives which are locally in L∞. This representation turns out to be optimal as can already be demonstrated with the help of hydrogenic wave functions. The proofs of these results are, in an essential way, based on a new elliptic regularity result which is of independent interest. Some identities that can be interpreted as cusp conditions for second order derivatives of ψ are derived.

The Electron Density is Smooth Away from the Nuclei

We prove that the electron densities of electronic eigenfunctions of atoms and molecules are smooth away from the nuclei.

Analyticity of the density of electronic wavefunctions

We prove that the electronic densities of atomic and molecular eigenfunctions are real analytic inR3 away from the nuclei.

The Ground State Energy of the Three Dimensional Ginzburg-Landau Functional Part I: Bulk Regime

We consider the Ginzburg-Landau functional defined over a bounded and smooth three dimensional domain. Supposing that the magnetic field is comparable with the second critical field and that the Ginzburg-Landau parameter is large, we determine a precise asymptotic formula for the minimizing energy. In particular, this shows how bulk superconductivity decreases in average as the applied magnetic field approaches the second critical field from below. Other estimates are also obtained which allow us to obtain, in a subsequent paper [19], a fine characterization of the second critical field. The approach relies on a careful analysis of several limiting energies, which is of independent interest.

Superconductivity between HC2 and HC3

Superconductivity for Type II superconductors in external magnetic fields of magnitude between the second and third critical fields is known to be restricted to a narrow boundary region. The profile of the superconducting order parameter in the Ginzburg–Landau model is expected to be governed by an effective one-dimensional model. This is known to be the case for external magnetic fields sufficiently close to the third critical field. In this text we prove such a result on a larger interval of validity.

A uniqueness theorem for higher order anharmonic oscillators

We study for

On the energy of bound states for magnetic Schrödinger operators

\alpha\in\R

Self-Adjointness of Two-Dimensional Dirac Operators on Domains

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Relativistic Scott correction in self-generated magnetic fields

k \in {\mathbb N} \setminus \{0\}