Calendar of Physics Talks Vienna

Fingerprints of Magnetism in Transport and Force Measurements by STM/AFM
Speaker:Dr. Peter Jacobson (Max-Planck-Institute for Solid State Research, Stuttgart/Germany)
Abstract:In order to engineer the magnetism of quantum devices, it is necessary to quantify how the structural and chemical environment of the junction influences the spin. Metrics such as coordination number or symmetry provide a simple method to quantify the local environment, but neglect the many-body interactions of an impurity spin when coupled to contacts. We have utilized the highly corrugated hexagonal boron nitride (h-BN) monolayer to mediate the coupling between a cobalt spin in CoHx (x=1,2) complexes and the metal contact. While the hydrogen atoms control the total effective spin, the corrugation is found to smoothly tune the Kondo exchange interaction between the spin and the underlying metal. Using scanning tunneling microscopy and spectroscopy together with numerical simulations, we quantitatively demonstrate how the Kondo exchange interaction mimics chemical tailoring and changes
Date: Tue, 26.05.2015
Time: 16:00
Location:Technische Universität Wien, Institut für Angewandte Physik, E134 yellow tower „B“, 5th floor, Seminarraum 134A (room number DB05L03) 1040 Wien, Wiedner Hauptstraße 8-10
Contact:Univ.Prof. Dr. Ulrike Diebold/Dr.Gareth Parkinson

Visualizing Limits of Spacetimes
Speaker:Emma Jakobsson (Stockholm)
Abstract:The limit obtained when letting a free parameter of a spacetime approach a certain value is in general not unique, but depends on the choice of coordinates. This ambiguity led Geroch to formulate a definition of limits of a one-parameter family of spacetimes in 1969. We have come up with an application of Geroch’s definition, which makes it possible to see the limiting procedure in pictures. The general idea is to let the spacetime under consideration---if possible---be represented by a 1+1-dimensional surface reflecting its essential causal structure, and embed this surface in 2+1-dimensional anti-de Sitter space. With the help of a conformally compactified picture of adS3 the result is reminiscent of a Penrose diagram, with the difference that the picture will change as we vary the parameter. The examples considered here are two different limits obtained when letting the charge . .
Date: Thu, 28.05.2015
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Some rigidity results for static metrics
Speaker:Lorenzo Mazzieri (Pisa)
Abstract:im Rahmen des Lunchseminars der Gravitationsphysik: We present a new approach to the study of asymptotically flat static metrics in general relativity. Our method works in every dimension and it is based on a conformal splitting technique, which has been previously applied by the authors to the study of the geometric aspects of classical potential theory. The results are obtained in collaboration with V. Agostiniani.
Date: Fri, 29.05.2015
Time: 13:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, common room, 1. Stock
Contact:P.T. Chrusciel