16,495 research outputs found

    Telegraph Noise in Coupled Quantum Dot Circuits Induced by a Quantum Point Contact

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    Charge detection utilizing a highly biased quantum point contact has become the most effective probe for studying few electron quantum dot circuits. Measurements on double and triple quantum dot circuits is performed to clarify a back action role of charge sensing on the confined electrons. The quantum point contact triggers inelastic transitions, which occur quite generally. Under specific device and measurement conditions these transitions manifest themselves as bounded regimes of telegraph noise within a stability diagram. A nonequilibrium transition from artificial atomic to molecular behavior is identified. Consequences for quantum information applications are discussed.Comment: 4 pages, 3 figures (as published

    Assessing digital preservation frameworks: the approach of the SHAMAN project

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    How can we deliver infrastructure capable of supporting the preservation of digital objects, as well as the services that can be applied to those digital objects, in ways that future unknown systems will understand? A critical problem in developing systems is the process of validating whether the delivered solution effectively reflects the validated requirements. This is a challenge also for the EU-funded SHAMAN project, which aims to develop an integrated preservation framework using grid-technologies for distributed networks of digital preservation systems, for managing the storage, access, presentation, and manipulation of digital objects over time. Recognising this, the project team ensured that alongside the user requirements an assessment framework was developed. This paper presents the assessment of the SHAMAN demonstrators for the memory institution, industrial design and engineering and eScience domains, from the point of view of user’s needs and fitness for purpose. An innovative synergistic use of TRAC criteria, DRAMBORA risk registry and mitigation strategies, iRODS rules and information system models requirements has been designed, with the underlying goal to define associated policies, rules and state information, and make them wherever possible machine-encodable and enforceable. The described assessment framework can be valuable not only for the implementers of this project preservation framework, but for the wider digital preservation community, because it provides a holistic approach to assessing and validating the preservation of digital libraries, digital repositories and data centres

    Anomalous resistance overshoot in the integer quantum Hall effect

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    In this work we report experiments on defined by shallow etching narrow Hall bars. The magneto-transport properties of intermediate mobility two-dimensional electron systems are investigated and analyzed within the screening theory of the integer quantized Hall effect. We observe a non-monotonic increase of Hall resistance at the low magnetic field ends of the quantized plateaus, known as the overshoot effect. Unexpectedly, for Hall bars that are defined by shallow chemical etching the overshoot effect becomes more pronounced at elevated temperatures. We observe the overshoot effect at odd and even integer plateaus, which favor a spin independent explanation, in contrast to discussion in the literature. In a second set of the experiments, we investigate the overshoot effect in gate defined Hall bar and explicitly show that the amplitude of the overshoot effect can be directly controlled by gate voltages. We offer a comprehensive explanation based on scattering between evanescent incompressible channels.Comment: 7 pages and 5 figure

    Conceptual design for measuring soil management sustainability

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    Soils are the nexus of food, energy and water which illustrates the need for a holistic approach in sustainable soil management. The search for relevant bioindicators of soil sustainability has led to a huge output of studies recently, but yet a proper parameter or a set of parameters has not been identified. Resilience is often promoted to be a boundary concept to integrate social and natural dimensions of sustainability. Therefore, resilience is a promising parameter when it comes to measuring sustainability of soil management practices, since it reflects both its highly interlinked ecological and management components. To include both of these two interlinked components, the whole concept of soil ecosystem functioning needs to be reconsidered. We will present a modified concept of soil functioning cycles within the three dimensions of potential, connectedness and resilience. Additionally, we present a first methodological approach of how to measure resilience by the maximum ecological performance (MEP), using the multi-omics approach. We will present resilience as a key element of an adaptive management scheme, to also meet the challenge of deriving information about the link between soil biodiversity and soil multifunctionality
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