Positivity of Lyapunov exponents for Anderson-type models on two coupled strings.
Proof of a conjecture about atomic and molecular cores related to Scott's correction.
Propagation des mesures de Wigner à travers un croisement de codimension 1 dégénéré
Propagation estimates for Dirac operators and application to scattering theory
In this paper, we prove propagation estimates for a massive Dirac equation in flat spacetime. This allows us to construct the asymptotic velocity operator and to analyse its spectrum. Eventually, using this new information, we are able to obtain complete scattering results; that is to say we prove the existence and the asymptotic completeness of the Dollard modified wave operators.
Quantization effects for a variant of the Ginzburg-Landau type system.
Quantum diffusion and generalized Rényi dimensions of spectral measures
We estimate the spreading of the solution of the Schrödinger equation asymptotically in time, in term of the fractal properties of the associated spectral measures. For this, we exhibit a lower bound for the moments of order at time for the state defined by . We show that this lower bound can be expressed in term of the generalized Rényi dimension of the spectral measure associated to the hamiltonian and the state . We especially concentrate on continuous models.
Recent results on Lieb-Thirring inequalities
We give a survey of results on the Lieb-Thirring inequalities for the eigenvalue moments of Schrödinger operators. In particular, we discuss the optimal values of the constants therein for higher dimensions. We elaborate on certain generalisations and some open problems as well.
Recovering quantum graphs from their Bloch spectrum
We define the Bloch spectrum of a quantum graph to be the map that assigns to each element in the deRham cohomology the spectrum of an associated magnetic Schrödinger operator. We show that the Bloch spectrum determines the Albanese torus, the block structure and the planarity of the graph. It determines a geometric dual of a planar graph. This enables us to show that the Bloch spectrum indentifies and completely determines planar -connected quantum graphs.
Reduced and extended weak coupling limit
The main aim of our lectures is to give a pedagogical introduction to various mathematical formalisms used to describe open quantum systems: completely positive semigroups, dilations of semigroups, quantum Langevin dynamics and the so-called Pauli-Fierz Hamiltonians. We explain two kinds of the weak coupling limit. Both of them show that Hamiltonian dynamics of a small quantum system interacting with a large resevoir can be approximated by simpler dynamics. The better known reduced weak coupling...
Refined Algebraic Quantization: Systems with a single constraint
This paper explores in some detail a recent proposal (the Rieffel induction/refined algebraic quantization scheme) for the quantization of constrained gauge systems. Below, the focus is on systems with a single constraint and, in this context, on the uniqueness of the construction. While in general the results depend heavily on the choices made for certain auxiliary structures, an additional physical argument leads to a unique result for typical cases. We also discuss the 'superselection laws' that...
Remark on Essential Selfadjointness of Dirac Operators with Coulomb Potentials.
Remarks on relativistic Schrödinger operators and their extensions
Renormalization of exponential sums and matrix cocycles
In this paper, we present a new point of view on the renormalization of some exponential sums stemming from number theory. We generalize this renormalization procedure to study some matrix cocycles arising in spectral problems of quantum mechanics
Resolvent estimates for scalar fields with electromagnetic perturbation.
Resonance theory of two-body Schrödinger operators
Resonances and Spectral Shift Function near the Landau levels
We consider the 3D Schrödinger operator where , is a magnetic potential generating a constant magneticfield of strength , and is a short-range electric potential which decays superexponentially with respect to the variable along the magnetic field. We show that the resolvent of admits a meromorphic extension from the upper half plane to an appropriate Riemann surface , and define the resonances of as the poles of this meromorphic extension. We study their distribution near any fixed...
Resonances of relativistic Schrödinger operators with homogeneous electric fields
Résonances près d’une énergie critique
Dans cet exposé, on décrit un travail effectué sous la direction de J. Sjöstrand. On prouve des majorations et des minorations du nombre de résonances d’un opérateur de Schrödinger semi-classique dans des petits disques centrés en , une valeur critique de .
Résonances semi-classiques pour l'opérateur de Schrödinger matriciel en dimension deux
Rieffel’s pseudodifferential calculus and spectral analysis of quantum Hamiltonians
We use the functorial properties of Rieffel’s pseudodifferential calculus to study families of operators associated to topological dynamical systems acted by a symplectic space. Information about the spectra and the essential spectra are extracted from the quasi-orbit structure of the dynamical system. The semi-classical behavior of the families of spectra is also studied.