Vorträge

I'll start with a short recap of the lattice Anderson
model, with a focus on Minami's estimate and its applications. In
particular it implies Poissonian local eigenvalue statistics, which
is believed to be a characteristic feature of spectrally localized
quantum mechanical systems. In the second part of the talk I'll
present our main technical result, a level-spacing estimate for
continuum random Schrödinger operators, and argue why it implies
Poissonian local eigenvalue statistics. If time permits I'll comment
on the proof's methods.
The talk is based on joint work with Alexander Elgart.

We are going to discuss (again) the approach of describing fractional powers of linear operators on
Banach spaces as it was performed by Silvestre and Caffarelli when they were studying the fractional
Laplacian. Even though useful it is still an open problem whether this is possible for all sectorial
operators and, if so, whether it is unique.
The presented content is work in progress.

The study of electromagnetic fields in 2D circuits often leads to resonances. We use a polynomial chaos expansion (due to uncertain circuit parameters), which is analytically and numerically troublesome near the resonance frequencies. As a toy model for the convergence of the polynomial chaos expansion, we look at the parallel RLC circuit with uncertain capacitance and give $L^2$ error bounds depending on the degree of the expansion, the random distribution, the distance to resonance and the so-called quality factor of the circuit (which is a measure for the damping).

Im Rahmen des Lothar-Collatz-Seminars spreche ich am Geomatikum (Uni Hamburg) über strukturierte Pseudospektren in der Systemtheorie.

Abstract: https://www.c3s.uni-hamburg.de/en/news-events/seminar-c3s/gallaun.pdf