7,909 research outputs found

    Covariant spinor representation of iosp(d,2/2)iosp(d,2/2) and quantization of the spinning relativistic particle

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    A covariant spinor representation of iosp(d,2/2)iosp(d,2/2) is constructed for the quantization of the spinning relativistic particle. It is found that, with appropriately defined wavefunctions, this representation can be identified with the state space arising from the canonical extended BFV-BRST quantization of the spinning particle with admissible gauge fixing conditions after a contraction procedure. For this model, the cohomological determination of physical states can thus be obtained purely from the representation theory of the iosp(d,2/2)iosp(d,2/2) algebra.Comment: Updated version with references included and covariant form of equation 1. 23 pages, no figure

    Analysis of the linearity characteristics, tape recorders and compensation effects in the FM/FM telemetry system

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    Linearity characteristics, tape recorder effects, and tape speed compensation effects in FM/FM TELEMETRY syste

    Polynomial super-gl(n) algebras

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    We introduce a class of finite dimensional nonlinear superalgebras L=L0ˉ+L1ˉL = L_{\bar{0}} + L_{\bar{1}} providing gradings of L0ˉ=gl(n)sl(n)+gl(1)L_{\bar{0}} = gl(n) \simeq sl(n) + gl(1). Odd generators close by anticommutation on polynomials (of degree >1>1) in the gl(n)gl(n) generators. Specifically, we investigate `type I' super-gl(n)gl(n) algebras, having odd generators transforming in a single irreducible representation of gl(n)gl(n) together with its contragredient. Admissible structure constants are discussed in terms of available gl(n)gl(n) couplings, and various special cases and candidate superalgebras are identified and exemplified via concrete oscillator constructions. For the case of the nn-dimensional defining representation, with odd generators Qa,QˉbQ_{a}, \bar{Q}{}^{b}, and even generators Eab{E^{a}}_{b}, a,b=1,...,na,b = 1,...,n, a three parameter family of quadratic super-gl(n)gl(n) algebras (deformations of sl(n/1)sl(n/1)) is defined. In general, additional covariant Serre-type conditions are imposed, in order that the Jacobi identities be fulfilled. For these quadratic super-gl(n)gl(n) algebras, the construction of Kac modules, and conditions for atypicality, are briefly considered. Applications in quantum field theory, including Hamiltonian lattice QCD and space-time supersymmetry, are discussed.Comment: 31 pages, LaTeX, including minor corrections to equation (3) and reference [60

    The Stripe 82 1-2 GHz Very Large Array Snapshot Survey: Multiwavelength Counterparts

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    We have combined spectrosopic and photometric data from the Sloan Digital Sky Survey (SDSS) with 1.41.4 GHz radio observations, conducted as part of the Stripe 82 121-2 GHz Snapshot Survey using the Karl G. Jansky Very Large Array (VLA), which covers 100\sim100 sq degrees, to a flux limit of 88 μ\muJy rms. Cross-matching the 1176811\,768 radio source components with optical data via visual inspection results in a final sample of 47954\,795 cross-matched objects, of which 19961\,996 have spectroscopic redshifts and 27992\,799 objects have photometric redshifts. Three previously undiscovered Giant Radio Galaxies (GRGs) were found during the cross-matching process, which would have been missed using automated techniques. For the objects with spectroscopy we separate radio-loud Active Galactic Nuclei (AGN) and star-forming galaxies (SFGs) using three diagnostics and then further divide our radio-loud AGN into the HERG and LERG populations. A control matched sample of HERGs and LERGs, matched on stellar mass, redshift and radio luminosity, reveals that the host galaxies of LERGs are redder and more concentrated than HERGs. By combining with near-infrared data, we demonstrate that LERGs also follow a tight KzK-z relationship. These results imply the LERG population are hosted by population of massive, passively evolving early-type galaxies. We go on to show that HERGs, LERGs, QSOs and star-forming galaxies in our sample all reside in different regions of a WISE colour-colour diagram. This cross-matched sample bridges the gap between previous `wide but shallow' and `deep but narrow' samples and will be useful for a number of future investigations.Comment: 17 pages, 19 figures. Resubmitted to MNRAS after the initial comment

    Goonhilly: a new site for e-MERLIN and the EVN

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    The benefits for the e-MERLIN and EVN arrays of using antennae at the satellite communication station at Goonhilly in Cornwall are discussed. The location of this site - new to astronomy - will provide an almost equal distribution of long baselines in the east-west- and north-south directions, and opens up the possibility to get significantly improved observations of equatorial fields with e-MERLIN. These additional baselines will improve the sensitivity on a set of critical spatial scales and will increase the angular resolution of e-MERLIN by a factor of two. e-MERLIN observations, including many allocated under the e-MERLIN Legacy programme, will benefit from the enhanced angular resolution and imaging capability especially for sources close to or below the celestial equator (where ESO facilities such as ALMA will operate) of including the Goonhilly telescopes. Furthermore, the baselines formed between Goonhilly and the existing stations will close the gap between the baselines of e-MERLIN and those of the European VLBI Network (EVN) and therefore enhance the legacy value of e-MERLIN datasets.Comment: 10 pages, 2 figue

    On the Structure of the Observable Algebra of QCD on the Lattice

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    The structure of the observable algebra OΛ{\mathfrak O}_{\Lambda} of lattice QCD in the Hamiltonian approach is investigated. As was shown earlier, OΛ{\mathfrak O}_{\Lambda} is isomorphic to the tensor product of a gluonic CC^{*}-subalgebra, built from gauge fields and a hadronic subalgebra constructed from gauge invariant combinations of quark fields. The gluonic component is isomorphic to a standard CCR algebra over the group manifold SU(3). The structure of the hadronic part, as presented in terms of a number of generators and relations, is studied in detail. It is shown that its irreducible representations are classified by triality. Using this, it is proved that the hadronic algebra is isomorphic to the commutant of the triality operator in the enveloping algebra of the Lie super algebra sl(1/n){\rm sl(1/n)} (factorized by a certain ideal).Comment: 33 page

    Comprehensive analysis of Hox gene expression in the amphipod crustacean Parhyale hawaiensis.

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    Hox genes play crucial roles in establishing regional identity along the anterior-posterior axis in bilaterian animals, and have been implicated in generating morphological diversity throughout evolution. Here we report the identification, expression, and initial genomic characterization of the complete set of Hox genes from the amphipod crustacean Parhyale hawaiensis. Parhyale is an emerging model system that is amenable to experimental manipulations and evolutionary comparisons among the arthropods. Our analyses indicate that the Parhyale genome contains a single copy of each canonical Hox gene with the exception of fushi tarazu, and preliminary mapping suggests that at least some of these genes are clustered together in the genome. With few exceptions, Parhyale Hox genes exhibit both temporal and spatial colinearity, and expression boundaries correlate with morphological differences between segments and their associated appendages. This work represents the most comprehensive analysis of Hox gene expression in a crustacean to date, and provides a foundation for functional studies aimed at elucidating the role of Hox genes in arthropod development and evolution

    Expanding e-MERLIN with the Goonhilly Earth Station

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    A consortium of universities has recently been formed with the goal of using the decommissioned telecommunications infrastructure at the Goonhilly Earth Station in Cornwall, UK, for astronomical purposes. One particular goal is the introduction of one or more of the ~30-metre parabolic antennas into the existing e-MERLIN radio interferometer. This article introduces this scheme and presents some simulations which quantify the improvements that would be brought to the e-MERLIN system. These include an approximate doubling of the spatial resolution of the array, an increase in its N-S extent with strong implications for imaging the most well-studied equatorial fields, accessible to ESO facilities including ALMA. It also increases the overlap between the e-MERLIN array and the European VLBI Network. We also discuss briefly some niche science areas in which an e-MERLIN array which included a receptor at Goonhilly would be potentially world-leading, in addition to enhancing the existing potential of e-MERLIN in its role as a Square Kilometer Array pathfinder instrument.Comment: 7 pages, 3 figures, to appear in the proceedings of "Astronomy with megastructures: Joint science with the E-ELT and SKA", 10-14 May 2010, Crete, Greece (Eds: Isobel Hook, Dimitra Rigopoulou, Steve Rawlings and Aris Karastergiou

    Symmetric Instantons and Skyrme Fields

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    By explicit construction of the ADHM data, we prove the existence of a charge seven instanton with icosahedral symmetry. By computing the holonomy of this instanton we obtain a Skyrme field which approximates the minimal energy charge seven Skyrmion. We also present a one parameter family of tetrahedrally symmetric instantons whose holonomy gives a family of Skyrme fields which models a Skyrmion scattering process, where seven well-separated Skyrmions collide to form the icosahedrally symmetric Skyrmion.Comment: 22 pages plus 1 figure in GIF forma
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