46,921 research outputs found

    Scaling behaviour in random non-commutative geometries

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    Random non-commutative geometries are a novel approach to taking a non-perturbative path integral over geometries. They were introduced in arxiv.org/abs/1510.01377, where a first examination was performed. During this examination we found that some geometries show indications of a phase transition. In this article we explore this phase transition further for geometries of type (1,1)(1,1), (2,0)(2,0), and (1,3)(1,3). We determine the pseudo critical points of these geometries and explore how some of the observables scale with the system size. We also undertake first steps towards understanding the critical behaviour through correlations and in determining critical exponents of the system.Comment: 16 pages, 16 figures (v2: updated after review

    Results and Perspectives of the Auger Engineering Radio Array

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    The Auger Engineering Radio Array (AERA) is an extension of the Pierre Auger Cosmic-Ray Observatory. It is used to detect radio emission from extensive air showers with energies beyond 1017 10^{17}~eV in the 3080 30 - 80~MHz frequency band. After three phases of deployment, AERA now consists of more than 150 autonomous radio stations with different spacings, covering an area of about 17 17~km2^2. It is located at the same site as other Auger low-energy detector extensions enabling combinations with various other measurement techniques. The radio array allows different technical schemes to be explored as well as cross-calibration of our measurements with the established baseline detectors of the Auger Observatory. We report on the most recent technological developments and give an overview of the experimental results obtained with AERA. In particular, we will present the measurement of the radiation energy, i.e., the amount of energy that is emitted by the air shower in the form of radio emission, and its dependence on the cosmic-ray energy by comparing with the measurement of the the well-calibrated Auger surface detector. Furthermore, we outline the relevance of this result for the absolute calibration of the energy scale of cosmic-ray observatories.Comment: To be published in the Proceedings of the ARENA2016 conference, Groningen, The Netherland

    Semantic Squirrels

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    We argue that data should be acquired now. Every day that goes by data is lost. We propose Semantic Squirrels, a community-enabled low technology solution to data acquisition to achieve this data acquisition, while other more difficult problems wait to be resolved

    The Bard on the Brain

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    Observing observatories: web observatories should use linked data

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    Web Observatories are a major international scientific collaboration concerned with data sources of a heterogeneous nature, and often quite large. Of course, they are not the first such collaboration; the Web itself was born as a response to a similar scientific endeavor. It is therefore appropriate to look at other col-laborative activities, and try to learn and use the lessons they have learnt.We argue that Web Observatories should build in interoperability using current best practices right from the start. We also argue that Linked Data is a best practice, and can provide the basis for a research environment that will deliver the vision of a large group of cooperating Observatories, sharing data and re-search results to the benefit of all. In addition, we argue that the activity should not start with a major standardization process, but should grow around appro-priate standards as required

    ARIANNA: Measurement of cosmic rays with a radio neutrino detector in Antarctica

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    The ARIANNA detector aims to detect neutrinos with energies above \SI{e16}{eV} by instrumenting 0.5 Teratons of ice with a surface array of a thousand independent radio detector stations in Antarctica. The Antarctic ice is transparent to the radio signals caused by the Askaryan effect which allows for a cost-effective instrumentation of large volumes. Several pilot stations are currently operating successfully at the Moore's Bay site (Ross Ice Shelf) and at the South Pole. As the ARIANNA detector stations are positioned at the surface, the more abundant cosmic-ray air showers are also measured and serve as a direct way to prove the capabilities of the detector. We will present measured cosmic rays and will show how the incoming direction, polarization and electric field of the cosmic-ray pulse can be reconstructed from single detector stations comprising 4 upward and 4 downward facing LPDA antennas.Comment: Proceedings of the 8th International Conference on Acoustic and Radio EeV Neutrino Detection Activities, ARENA 201
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