Agenda
Mercredi 10 novembre 2021
Étude semiclassique de l’interaction d’Yukawa et ses champs asymptotiques
Zied Amarri, Université de Rennes
Quantum graphs with uncommon vertex couplings
Pavel Exner, Université de Prague
The main topic of this talk are quantum graphs with the vertex coupling violating the time-reversal invariance. We explain why such systems can be useful in physics and as a case study we analyze a simple example in which the asymmetry is maximal at a fixed energy. This leads to an interesting property, namely that high-energy scattering depends crucially on the vertex parity ; we will demonstrate implications of this fact for spectral and transport properties in several classes of graphs, both finite and infinite periodic ones. We will also discuss other time-asymmetric graphs and identify a class of such couplings which exhibits a nontrivial PT-symmetry despite being self-adjoint. The results come from a common work with Marzieh Baradaran, JirI Lipovsky , and Milos Tater.