28,670 research outputs found

    KΛ(1405)K\Lambda(1405) configuration of the KKˉNK\bar{K}N system

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    We study the KΛ(1405)K\Lambda(1405) configuration of the KKˉNK\bar{K}N system by considering KπΣK\pi\Sigma as a coupled channel. We solve the Faddeev equations for these systems and find confirmation of the existence of a new N∗N^{*} resonance around 1920 MeV with Jπ=1/2+J^{\pi}=1/2^{+} predicted in a single-channel potential model and also found in a Faddeev calculation as an a0(980)Na_{0}(980)N state, with the a0(980)a_{0}(980) generated in the KKˉK\bar{K}, πη\pi\eta interaction.Comment: Published versio

    RDF-TR: Exploiting structural redundancies to boost RDF compression

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    The number and volume of semantic data have grown impressively over the last decade, promoting compression as an essential tool for RDF preservation, sharing and management. In contrast to universal compressors, RDF compression techniques are able to detect and exploit specific forms of redundancy in RDF data. Thus, state-of-the-art RDF compressors excel at exploiting syntactic and semantic redundancies, i.e., repetitions in the serialization format and information that can be inferred implicitly. However, little attention has been paid to the existence of structural patterns within the RDF dataset; i.e. structural redundancy. In this paper, we analyze structural regularities in real-world datasets, and show three schema-based sources of redundancies that underpin the schema-relaxed nature of RDF. Then, we propose RDF-Tr (RDF Triples Reorganizer), a preprocessing technique that discovers and removes this kind of redundancy before the RDF dataset is effectively compressed. In particular, RDF-Tr groups subjects that are described by the same predicates, and locally re-codes the objects related to these predicates. Finally, we integrate RDF-Tr with two RDF compressors, HDT and k2-triples. Our experiments show that using RDF-Tr with these compressors improves by up to 2.3 times their original effectiveness, outperforming the most prominent state-of-the-art techniques

    Van der Waals spin valves

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    We propose spin valves where a 2D non-magnetic conductor is intercalated between two ferromagnetic insulating layers. In this setup, the relative orientation of the magnetizations of the insulating layers can have a strong impact on the in-plane conductivity of the 2D conductor. We first show this for a graphene bilayer, described with a tight-binding model, placed between two ferromagnetic insulators. In the anti-parallel configuration, a band gap opens at the Dirac point, whereas in the parallel configuration, the graphene bilayer remains conducting. We then compute the electronic structure of graphene bilayer placed between two monolayers of the ferromagnetic insulator CrI3_3, using density functional theory. Consistent with the model, we find that a gap opens at the Dirac point only in the antiparallel configuration.Comment: 5 pages, 4 figure
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