Electron Transport in a Mesoscopic Annulus, Driven by a Time-Dependent Magnetic Flux

Classical and quantum electron transport in an annulus formed by a two-dimensional electron gas in a perpendicular magnetic field is studied. The transport is driven by an enclosed time-dependent magnetic flux, and is described with a Landauer-Büttiker-type formalism. Transport current is generated because the transmission and reflection probabilities of the electrons which are emitted by the reservoirs on the inside and outside of the annulus are modified from their static values. The role of the probes, as well as the effect of scattering between the inside and outside of the annulus, is studied

The Potential of In-train Crowdsourcing

Nowadays railway operators are improving their services by offering IT-services within their trains. This paper reports on a design study we performed at Dutch Railways (Nederlandse Spoorwegen, NS) in order to research whether or not NS can crowdsource activities utilizing the novel in-train IT infrastructure it is currently rolling out, and provide their passengers a better journey experience at the same time. We specifically focused the potential of future services an the users intention to use the service over time. The study followed a design cycle, in which we created artefacts, and analysed adoption of these artefacts utilizing an in-train survey. Despite the limited scope of the study we can conclude that there is potential for in-train crowdsourcing. Passengers do show interest in the applications we designed, and the more general concept of in-train interaction. Adoption is more likely to occur when serious applications are used, as opposed to entertainment applications

Injection of Ballistic Hot Electrons and Cool Holes in a Two-Dimensional Electron Gas

We have constructed a novel magnetic spectrometer to study the dynamics of hot electrons and cool missing electron states injected by quantum point contacts in the two-dimensional electron gas of a GaAs-AlxGa1-xAs heterostructure. The mean free path of these quasi-particles is found to be longer than recent theoretical estimates. The injection energy of the particles is found to be anomalously low as the point contact approaches pinch-off, and also for high bias voltages.