The topological solitons, or “skyrmions”, in a planar ferromagnet experience a Magnus force proportional to the product of their velocity and the surrounding magnetization. It has been suggested that the charged quasiparticles near filling factor ν = 1 in the GaAs quantum Hall effect are skyrmions. If so, we might expect this spin-induced Magnus force to act on the quasiparticles in addition to...

Approximate resolution of linear systems of differential equationswith varying coefficients is a recurrent problem, shared by a number of scientific and engineering areas, ranging from QuantumMechanics to Control Theory. When formulated in operator or matrix form, the Magnus expansion furnishes an elegant setting to build up approximate exponential representations of the solution of the system....

Floquet theory provides rigorous foundations for the theory of periodically driven quantum systems. In the case of non-periodic driving, however, the situation is not so well understood. Here, we provide a critical review of the theoretical framework developed for quasi-periodically driven quantum systems. Although the theoretical footing is still under development, we argue that quasiperiodica...

1227. Familiality of fatal measles infections in Iceland, 1882. Analysis of a reconstructed patient cohort from a major epidemic Magnus Gottfredsson, MD, PhD; Sandra Gunnarsdottir, BS; Haraldur Briem, MD, PhD; Ingileif Jonsdottir, PhD; Kari Stefansson, MD, PhD; Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Infectious Diseases, Landspitali University Hospital, Reykjavik, Icelan...

1. Henrekson suggests that I draw ‘normative’ conclusions regarding the optimal level of selfemployment. I do not. I have simply argued that there is neither empirical evidence nor theory that tells us what the optimal rate of self-employment is or should be. Consequently, it is virtually impossible to know at any one moment of time whether a higher or lower selfemployment rate is better. For a...

In this brief review we describe the coming of age of Magnus expansions as an asymptotic and numerical tool in the investigation of linear differential equations in a Lie-group and homogeneous-space setting. Special attention is afforded to the many connections between modern theory of geometric numerical integration and other parts of mathematics: from abstract algebra to differential geometry...

Franc J.G.M. Klaassen, PhD (1) and Prof. Jan R. Magnus, PhD (2) 1. Department of Economics, University of Amsterdam, Roetersstraat 11, 1018 WB Amsterdam, The Netherlands. Tel: +31-205254191, Fax: +31-20-5254254. E-mail: [email protected]. 2. CentER for Economic Research, Tilburg University, PO Box 90153, 5000 LE Tilburg, The Netherlands. Tel: +31-13-4663092, Fax: +31-134663066. E-mail: magnus@u...