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A: Fachverband Atomphysik

A 8: Atomic systems in external fields II

A 8.5: Vortrag

Montag, 29. Februar 2016, 15:30–15:45, f303

An improved method for finding exceptional points and application to Rydberg systems in external fields — •Matthias Feldmaier, Jörg Main, and Günter Wunner — 1. Institut für Theoretische Physik, 70550 Stuttgart, Germany

Exceptional points are special places in the spectrum of open quantum systems, where resonances degenerate and the associated eigenvectors coalesce. An example for such a system is the hydrogen atom in parallel electric and magnetic fields, for which we solve the Schrödinger equation in a complete basis to calculate the resonances and eigenvectors. Starting from an avoided crossing within the term scheme and using a two-dimensional matrix model, we develop an iterative algorithm to calculate both the position and energy of exceptional points, and to verify their basic properties. Additionally, we are able to visualize the wavefunctions of the degenerated states. We report the existence of various exceptional points. For the hydrogen atom these points are in an experimentally inaccessible regime of field strengths. However, excitons in cuprous oxide in parallel electric and magnetic fields as the corresponding hydrogen analog in a solid state provide a suitable system where the high-field regime can be reached at much smaller external fields and for which we propose an experiment to detect exceptional points.