Angular EPR paradox

The violation of local uncertainty relations is a valuable tool for detecting entanglement, especially in multi-dimensional systems. The orbital angular momentum of light provides such a multi-dimensional system. We study quantum correlations for the conjugate variables of orbital angular momentum and angular position. We determine an experimentally testable criterion for the demonstration of an angular version of the EPR paradox. For the interpretation of future experimental results from our proposed setup, we include a model for the indeterminacies inherent to the angular position measurement. For this measurement angular apertures are used to determine the probability density of the angle. We show that for a class of aperture functions a demonstration of an angular EPR paradox, according to our criterion, is to be expected.Comment: 21 pages, 9 figures, to be published in J. Mod. Opt. special issue on quantum imagin

Instantaneous modulations in time-varying complex optical potentials

We study the impact of a spatially homogeneous yet non-stationary dielectric permittivity on the dynamical and spectral properties of light. Our choice of potential is motivated by the interest in PT-symmetric systems as an extension of quantum mechanics. Because we consider a homogeneous and non-stationary medium, PT symmetry reduces to time-reversal symmetry in the presence of balanced gain and loss. We construct the instantaneous amplitude and angular frequency of waves within the framework of Maxwell's equations and demonstrate the modulation of light amplification and attenuation associated with the well-defined temporal domains of gain and loss, respectively. Moreover, we predict the splitting of extrema of the angular frequency modulation and demonstrate the associated shrinkage of the modulation period. Our theory can be extended for investigating similar time-dependent effects with matter and acoustic waves in PT-symmetric structures.Comment: 13 pages, 4 figure

A multi-level metadata approach for a public sector information data infrastructure

This paper describes an approach for representing and handling metadata about Public Sector Information data sets in a large scale data infrastructure as designed within ENGAGE, a project of the FP7 Research Infrastructures programme. A multi-level approach is adopted, allowing management of metadata at various levels of expressive power, and thus enabling different use cases and requirements to be served through a single platform. CERIF is being investigated as a common conceptual model to ensure information integra- tion from diverse sources without loss of meaning and furthermore as the basis for the generation of Linked Open Data. Through detailed mappings from common metadata schemata used for PSI it is shown that CERIF is a data model suitable for representing rich contextual metadata for the domain of governmental datasets

Matter-wave grating distinguishing conservative and dissipative interactions

We propose an optical grating for matter waves that separates molecules depending on whether their interaction with the light is conservative or dissipative. Potential applications include fundamental tests of quantum mechanics, measurement of molecular properties and the ability to selectively prepare matter waves with different internal temperatures

Quantum phases in a doped Mott insulator on the Shastry-Sutherland lattice

We propose the projected BCS wave function as the ground state for the doped Mott insulator SrCu2(BO3)2 on the Shastry-Sutherland lattice. At half filling this wave function yields the exact ground state. Adding mobile charge carriers, we find a strong asymmetry between electron and hole doping. Upon electron doping an unusual metal with strong valence bond correlations forms. Hole doped systems are d-wave RVB superconductors in which superconductivity is strongly enhanced by the emergence of inhomogeneous plaquette bond order.Comment: 4 pages, 3 figure

Modeling the semantics of contextual and content-specific research metadata using ontology languages: issues on combining CERIF and OWL

Current Research Information Systems (CRISs) enable the maintenance of information related to research activities of organizations and their members, including outputs or products from these activities. Such contextual information is of uttermost importance for the processing of datasets and with the retrieval of scientific documents, providing e.g. the key information on provenance and characteristics of research activities that are needed when searching for data or scholarly content. In the context of the expanding initiative of the Web of Linked Data, translating that information into semantic languages enables new ways of querying benefitting from the reuse of domain ontologies. In that direction, this paper reports on the engineering of an ontology based version of the CERIF standard for CRISs using the OWL language and a proposed mapping to research datasets

Streamlining the CERIF XML data exchange format: towards CERIF 2.0.

The Common European Research Information Format (CERIF) is an established standard for Current Research Information Systems (CRISs) facing the increasing need for information sharing and exchange. euroCRIS released the first official CERIF XML exchange format in 2007; it followed the structure of the relational data model. Based on experience with the format and consulting with the CRIS community on newer interoperation and exchange concepts, the authors proposed an update to the CERIF XML exchange format. This updated CERIF XML aimed at compactness with expression and backwards compatibility. With this article, we provide insight into the motivation for change, present the updated format, and finally outline possible next steps

Harmonising and formalising research administration profiles CASRAI / CERIF

CASRAI and CERIF are international standardisation initiatives in the domain of Research Information Management. CASRAI develops and maintains a standard extensible vocabulary and exchangeable data profiles that reflect the business requirements of involved stakeholders. A data profile specifies the maximal ideal space of its application with compliant data records. CERIF is a data model supplying standard formal syntax and declared semantics to preserve the meaning inherent in identified requirements. It enables the transformation of conceptual descriptions into formal representation thereof and thus their meaningful re-use as well as a semantically compliant and syntactically valid data interchange. With this paper we share the experience, and the lessons learned from the transformation of CASRAI profiles into CERIF XML through the example of an Abridged CV