Tamed tiger? : the new notion of national security and liberal democracy

Includes bibliography

Raman response of Stage-1 graphite intercalation compounds revisited

We present a detailed in-situ Raman analysis of stage-1 KC8, CaC6, and LiC6 graphite intercalation compounds (GIC) to unravel their intrinsic finger print. Four main components were found between 1200 cm-1 and 1700 cm-1, and each of them were assigned to a corresponding vibrational mode. From a detailed line shape analysis of the intrinsic Fano-lines of the G- and D-line response we precisely determine the position ({\omega}ph), line width ({\Gamma}ph) and asymmetry (q) from each component. The comparison to the theoretical calculated line width and position of each component allow us to extract the electron-phonon coupling constant of these compounds. A coupling constant {\lambda}ph < 0.06 was obtained. This highlights that Raman active modes alone are not sufficient to explain the superconductivity within the electron-phonon coupling mechanism in CaC6 and KC8.Comment: 6 pages, 3 figures, 2 table

Developing a Web-Based Question-Driven Audience Response System Supporting BYOD

Question-driven Audience Response Systems (ARSs) are in the focus of research since the 1960s. Since then, the technology has changed and therefore systems have evolved too. This work is about conception and implementation of the web-based ARS RealFeedback which uses the principle of bring your own device (BYOD). A state-of-the-art analysis compares the features of existing web-based ARSs. The most important findings are used for the conception and the implementation of the system. Thinking-aloud tests, and the first usages during lectures confirm that the chosen requirements are very significant and valuable for lecturers

What is the minimal systemic risk in financial exposure networks?

We quantify how much systemic risk can be eliminated in financial contract networks by rearranging their network topology. By using mixed integer linear programming, financial linkages are optimally organized, whereas the overall economic conditions of banks, such as capital buffers, total interbank assets and liabilities, and average risk-weighted exposure remain unchanged. We apply the new optimization procedure to 10 snapshots of the Austrian interbank market where we focus on the largest 70 banks covering 71% of the market volume. The optimization reduces systemic risk (measured in DebtRank) by about 70%, showing the huge potential that changing the network structure has on the mitigation of financial contagion. Existing capital levels would need to be scaled up by a factor of 3.3 to obtain similar levels of DebtRank. These findings underline the importance of macro-prudential rules that focus on the structure of financial networks. The new optimization procedure allows us to benchmark actual networks to networks with minimal systemic risk. We find that simple topological measures, like link density, degree assortativity, or clustering coefficient, fail to explain the large differences in systemic risk between actual and optimal networks. We find that if the most systemically relevant banks are tightly connected, overall systemic risk is higher than if they are unconnected

Dressed, noise- or disorder- resilient optical lattices

External noise is inherent in any quantum system, and can have especially strong effects for systems exhibiting sensitive many-body phenomena. We show how a dressed lattice scheme can provide control over certain types of noise for atomic quantum gases in the lowest band of an optical lattice, removing the effects of lattice amplitude noise to first order for particular choices of the dressing field parameters. We investigate the non-equilibrium many-body dynamics for bosons and fermions induced by noise away from this parameter regime, and also show how the same technique can be used to reduce spatial disorder in projected lattice potentials.Comment: 4+ Pages, 4 Figure

charge transfer, strain, and electron-phonon coupling in graphene layers

Graphite intercalation compounds (GICs) are an interesting and highly studied field since 1970’s. It has gained renewed interest since the discovery of superconductivity at high temperature for CaCinline image and the rise of graphene. Intercalation is a technique used to introduce atoms or molecules into the structure of a host material. Intercalation of alkali metals in graphite has shown to be a controllable procedure recently used as a scalable technique for bulk production of graphene, and nano-ribbons by induced exfoliation of graphite. It also creates supra-molecular interactions between the host and the intercalant, inducing changes in the electronic, mechanical, and physical properties of the host. GICs are the mother system of intercalation also employed in fullerenes, carbon nanotubes, graphene, and carbon-composites. We will show how a combination of Raman and inline image calculations of the density and the electronic band structure in GICs can serve as a tool to elucidate the electronic structure, electron–phonon coupling, charge transfer, and lattice parameters of GICs and the graphene layers within. This knowledge of GICs is of high importance to understand superconductivity and to set the basis for applications with GICs, graphene and other nano-carbon based materials like nanocomposites in batteries and nanoelectronic devices