2,847 research outputs found

    Thermodynamic behavior of trivalent gallium, aluminum and iron distributions in garnets

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    Data on distribution of ions of gallium, aluminum, and iron among tetrahedral and octahedral sites in garnet

    Tripartite Entanglement versus Tripartite Nonlocality in Three-Qubit Greenberger-Horne-Zeilinger-Class States

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    We analyze the relationship between tripartite entanglement and genuine tripartite nonlocality for three-qubit pure states in the Greenberger-Horne-Zeilinger class. We consider a family of states known as the generalized Greenberger-Horne-Zeilinger states and derive an analytical expression relating the three-tangle, which quantifies tripartite entanglement, to the Svetlichny inequality, which is a Bell-type inequality that is violated only when all three qubits are nonlocally correlated. We show that states with three-tangle less than 1/2 do not violate the Svetlichny inequality. On the other hand, a set of states known as the maximal slice states does violate the Svetlichny inequality, and exactly analogous to the two-qubit case, the amount of violation is directly related to the degree of tripartite entanglement.We discuss further interesting properties of the generalized Greenberger-Horne-Zeilinger and maximal slice states

    The evolution of the Hong Kong currency board during global exchange rate instability, 1967-1973

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    Hong Kong SAR is well known as one of the few economies to operate a form of currency board as the basis of its monetary system. This system arose out of colonial status and has been retained except for a period of floating from 1975-83 to the present day, with some amendments. This article explores the evolution of the Exchange Fund during a period of global exchange rate instability showing that the abandonment of the monetary anchor in 1975 was part of a series of innovations to the use of the Fund as the colonial government sought to manage the exchange rate risks posed by the collapse of the Bretton Woods system

    Photon Statistics of a Single Atom Laser

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    We consider a laser model consisting of a single four-level or three-level atom, an optical cavity, and an incoherent pump. Results for photon statistics for varying pump levels are obtained using a quantum trajectory algorithm. In particular, we calculate the mean photon number, Fano factor (which is the variance over the mean). We examine that the behavior of the single-atom device as β, the fraction of spontaneous emission into the lasing mode, is varied. Typical values considered for β are 0.01\u3cβ\u3c1.0. We find that for large enough β, lasing action, with properties similar to those predicted by semiclassical theories that factorize atom-field correlations and use a small-noise approximation, can occur. Squeezing can occur as β is increased. There is no evidence of a sharp phase transition from weakly excited thermal light to coherent light at a particular pump power. This is consistent with work on many-atom lasers with β values in the range considered here. As β is increased, the output goes from quasithermal light to coherent and finally to squeezed light, progressing into a fully quantum-mechanical regime. We also consider the effects of cavity damping and spontaneous emission rates on these results

    Homm-sw Networks-of-stories to value tangible and intangible heritage in museums

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    Social inclusion, lifelong learning and the regeneration of competence networks are key processes which foster innovation. Museums may play an important role in these processes and ICT can strongly support the effectiveness of the interventions required. Among them, digital tools used to tell stories are becoming increasingly popular. Narratives in new dimensions enable the formation of personal and community identities, and the construction of meanings [1] [2 ]. Hommsw supports multimedia narratives which enhance tangible and intangible heritage in education and cultural mediation, as well as in tourism. Developed by Officina Emilia (Italy) and Crafts Museum (India), the application is online at www.homm-museums-software.org. So far, it implements the engine for creating and managing the activity ‘networks-of-stories’, to create a nonlinear and open multimedia narration. [3],[4] In the last decade, digital storytelling has spread rapidly due to the growth and possibilities offered by new ICT devices [5] [6]. Together with crowd sourcing it can enrich the understanding of tangible and intangible heritage. Digital storytelling still faces some critical challenges: creation of content on tangible and intangible heritage, classification and re-use of existing documents and clips, cooperative and coordinated production of new content. Moreover, for effective exploratory paths and a more analytical approach to browsing material, contents must be set in the overall perspective of the narrations, to ensure narration is coherent. Finally, validation and dissemination of related outcomes must respect scientific standards. Homm-sw has tools that: support educators, also in contrasting learning difficulties, in developing inclusive and collaborative educational practices; support curators; facilitate crowd sourcing; create a personal web repository of contents and connections; share contents to be published, if approved by the administrator; create a network of contents and applications, at different levels for different users and specific needs. Homm-sw extends the museum experience. Before the visit: users can have a general look at museum contents and note, in their online personal desktop, what they are interested in. During the visit: users can retrieve their notes and add what is available on the museum’s exhibits and augmented reality, hands-on activities and multimedia contents, living laboratories, demonstration programs. Homm-sw in the onsite-mode allows only notes and memos, to fully enjoy what the museum uniquely offers. After the visit: users access their online workspace to retrieve and explore their notes, and any other content, as much as they wish. Beyond those common to other ICT tools in use in museums, Homm-sw has two key innovative functions. First, recording and retrieval of users' activities: during the visit in a museum, the visitor accessing her account may browse and take notes in her personal workspace and then retrieve and explore them, and many more, as much as she likes after the visit. Second, narratives presented through a set of related clips (videos, albums, texts) are easily seen in the conceptual map proposed by the curators. Homm-sw can be shared with non-profit organizations which intend to develop new features and share the upgrade with previous users and with new users, on the same conditions. Other engines will be implemented according to the demands of users, together with multi-channel and multilingual extension. As a tool for digital storytelling, integration with other software applications is welcome
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