One-loop stau masses in the effective potential approach

We calculate the one-loop contributions to the tau slepton masses in the Minimal Supersymmetric Standard Model in the effective potential approach. For the majority of parameter space under study, those corrections are shown to elevate the value of the lightest stau mass.Comment: 11 pages, 3 figure

Building an alternative social currency: Dematerialising and rematerialising digital money across media

This paper reports on the user experience and design of physical and digital forms of a mixed-media local currency. We reconceive digitally mediated transactions as social interactions and report on the development of conceptual designs informed by user research and interactive workshops. Our findings show that use is strongly tied to conceptions of locality and community, markers of identity, information exchange and the digital and physical forms as tools for shaping interactions. The form of the currency can make the invisible visible, exposing our identities and values, business models, and the details of the transactions themselves. Our analysis stresses the need to provide opportunities for extending social interaction, making more local connections and deriving the best value from those connections, without insulating individuals from each other, or from the wider geographical context. Themes that emerged from the user research were visualized as conceptual designs for digitally augmented media, allowing us to explore the monetary transaction at three levels: the material, as interaction between two parties, and the context of the transaction.The RCUK Digital Economy theme (EP/K012304/1)

Analysis in weak systems

The authors survey and comment their work on weak analysis. They describe the basic set-up of analysis in a feasible second-order theory and consider the impact of adding to it various forms of weak Konig's lemma. A brief discussion of the Baire categoricity theorem follows. It is then considered a strengthening of feasibility obtained (fundamentally) by the addition of a counting axiom and showed how it is possible to develop Riemann integration in the stronger system. The paper finishes with three questions in weak analysis.info:eu-repo/semantics/publishedVersio

Fundamental Oscillation Periods of the Interlayer Exchange Coupling beyond the RKKY Approximation

A general method for obtaining the oscillation periods of the interlayer exchange coupling is presented. It is shown that it is possible for the coupling to oscillate with additional periods beyond the ones predicted by the RKKY theory. The relation between the oscillation periods and the spacer Fermi surface is clarified, showing that non-RKKY periods do not bear a direct correspondence with the Fermi surface. The interesting case of a FCC(110) structure is investigated, unmistakably proving the existence and relevance of non-RKKY oscillations. The general conditions for the occurrence of non-RKKY oscillations are also presented.Comment: 34 pages, 10 figures ; to appear in J. Phys.: Condens. Mat

Exchange coupling between magnetic layers across non-magnetic superlattices

The oscillation periods of the interlayer exchange coupling are investigated when two magnetic layers are separated by a metallic superlattice of two distinct non-magnetic materials. In spite of the conventional behaviour of the coupling as a function of the spacer thickness, new periods arise when the coupling is looked upon as a function of the number of cells of the superlattice. The new periodicity results from the deformation of the corresponding Fermi surface, which is explicitly related to a few controllable parameters, allowing the oscillation periods to be tuned.Comment: 13 pages; 5 figures; To appear in J. Phys.: Cond. Matte