4,598 research outputs found

    Isomonodromic deformatiion with an irregular singularity and hyperelliptic curve

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    In this paper, we extend the result of Kitaev and Korotkin to the case where a monodromy-preserving deformation has an irregular singularity. For the monodromy-preserving deformation, we obtain the τ\tau-function whose deformation parameters are the positions of regular singularities and the parameter tt of an irregular singularity. Furthermore, the τ\tau-function is expressed by the hyperelliptic Θ\Theta function moving the argument \z and the period \B, where tt and the positions of regular singularities move zz and \B, respectively.Comment: 23 pages, 2 figure

    Semiclassical Strings in AdS_5 x S^5 and Automorphic Functions

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    Using AdS/CFT we derive from the folded spinning string ordinary differential equations for the anomalous dimension of the dual N=4 SYM twist-two operators at strong coupling. We show that for large spin the asymptotic solutions have the Gribov-Lipatov recirocity property. To obtain this result we use a hidden modular invariance of the energy-spin relation of the folded spinning string. Further we identify the Moch-Vermaseren-Vogt (MVV) relations, which were first recognized in plain QCD calculations, as the recurrence relations of the asymptotic series ansatz.Comment: 4 page

    Geometric collections and Castelnuovo-Mumford Regularity

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    The paper begins by overviewing the basic facts on geometric exceptional collections. Then, we derive, for any coherent sheaf \cF on a smooth projective variety with a geometric collection, two spectral sequences: the first one abuts to \cF and the second one to its cohomology. The main goal of the paper is to generalize Castelnuovo-Mumford regularity for coherent sheaves on projective spaces to coherent sheaves on smooth projective varieties XX with a geometric collection σ\sigma . We define the notion of regularity of a coherent sheaf \cF on XX with respect to σ\sigma. We show that the basic formal properties of the Castelnuovo-Mumford regularity of coherent sheaves over projective spaces continue to hold in this new setting and we show that in case of coherent sheaves on \PP^n and for a suitable geometric collection of coherent sheaves on \PP^n both notions of regularity coincide. Finally, we carefully study the regularity of coherent sheaves on a smooth quadric hypersurface Q_n \subset \PP^{n+1} (nn odd) with respect to a suitable geometric collection and we compare it with the Castelnuovo-Mumford regularity of their extension by zero in \PP^{n+1}.Comment: To appear in Math. Proc. Cambridg

    Low Rank Vector Bundles on the Grassmannian G(1,4)

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    Here we define the concept of LL-regularity for coherent sheaves on the Grassmannian G(1,4) as a generalization of Castelnuovo-Mumford regularity on Pn{\bf{P}^n}. In this setting we prove analogs of some classical properties. We use our notion of LL-regularity in order to prove a splitting criterion for rank 2 vector bundles with only a finite number of vanishing conditions. In the second part we give the classification of rank 2 and rank 3 vector bundles without "inner" cohomology (i.e. H^i_*(E)=H^i(E\otimes\Q)=0 for any i=2,3,4i=2,3,4) on G(1,4) by studying the associated monads.Comment: 11 pages, no figure

    Preconception care: it’s never too early

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    The preconception window has been recognized as one of the earliest sensitive windows of human development, and interventions that focus on this period have the potential to affect not only pregnancy but long term outcomes as well. The journal Reproductive Health has published a supplement entitled ‘Preconception Interventions’ which includes a series of systematic reviews regarding the impact of public health interventions during the preconception period on maternal and child health. These articles describe the role that poor preconception health plays in creating health disparities across the globe. The reviews highlight our current understanding (or lack thereof) regarding how both maternal and paternal preconception health and knowledge shapes the long-term health of not only children, but of families, communities, and nations. Researchers and healthcare workers should take particular note of these interventions, as the preconception time period may be as important as the pregnancy and post-pregnancy periods, and is critical in terms of bridging the gap in the continuum of care, particularly for adolescents.Fil: Mumford, Sunni L.. National Institutes of Health; Estados UnidosFil: Michels, Kara A.. National Institutes of Health; Estados UnidosFil: Salaria, Natasha. BioMed Central; Reino UnidoFil: Valanzasca, Pilar. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Belizan, Jose. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Topological quantum gate entangler for a multi-qubit state

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    We establish a relation between topological and quantum entanglement for a multi-qubit state by considering the unitary representations of the Artin braid group. We construct topological operators that can entangle multi-qubit state. In particular we construct operators that create quantum entanglement for multi-qubit states based on the Segre ideal of complex multi-projective space. We also in detail discuss and construct these operators for two-qubit and three-qubit states.Comment: 6 page

    Impurity in a Bose-Einstein condensate in a double well

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    We compare and contrast the mean-field and many-body properties of a Bose-Einstein condensate trapped in a double well potential with a single impurity atom. The mean-field solutions display a rich structure of bifurcations as parameters such as the boson-impurity interaction strength and the tilt between the two wells are varied. In particular, we study a pitchfork bifurcation in the lowest mean-field stationary solution which occurs when the boson-impurity interaction exceeds a critical magnitude. This bifurcation, which is present for both repulsive and attractive boson-impurity interactions, corresponds to the spontaneous formation of an imbalance in the number of particles between the two wells. If the boson-impurity interaction is large, the bifurcation is associated with the onset of a Schroedinger cat state in the many-body ground state. We calculate the coherence and number fluctuations between the two wells, and also the entanglement entropy between the bosons and the impurity. We find that the coherence can be greatly enhanced at the bifurcation.Comment: 19 pages, 17 figures. The second version contains minor corrections and some better figures (thicker lines

    Development of probabilistic models for quantitative pathway analysis of plant pest introduction for the EU territory

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    This report demonstrates a probabilistic quantitative pathway analysis model that can be used in risk assessment for plant pest introduction into EU territory on a range of edible commodities (apples, oranges, stone fruits and wheat). Two types of model were developed: a general commodity model that simulates distribution of an imported infested/infected commodity to and within the EU from source countries by month; and a consignment model that simulates the movement and distribution of individual consignments from source countries to destinations in the EU. The general pathway model has two modules. Module 1 is a trade pathway model, with a Eurostat database of five years of monthly trade volumes for each specific commodity into the EU28 from all source countries and territories. Infestation levels based on interception records, commercial quality standards or other information determine volume of infested commodity entering and transhipped within the EU. Module 2 allocates commodity volumes to processing, retail use and waste streams and overlays the distribution onto EU NUTS2 regions based on population densities and processing unit locations. Transfer potential to domestic host crops is a function of distribution of imported infested product and area of domestic production in NUTS2 regions, pest dispersal potential, and phenology of susceptibility in domestic crops. The consignment model covers the several routes on supply chains for processing and retail use. The output of the general pathway model is a distribution of estimated volumes of infested produce by NUTS2 region across the EU28, by month or annually; this is then related to the accessible susceptible domestic crop. Risk is expressed as a potential volume of infested fruit in potential contact with an area of susceptible domestic host crop. The output of the consignment model is a volume of infested produce retained at each stage along the specific consignment trade chain

    Automorphisms of moduli spaces of vector bundles over a curve

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    Let X be an irreducible smooth complex projective curve of genus g at least 4. Let M(r,\Lambda) be the moduli space of stable vector bundles over X or rank r and fixed determinant \Lambda, of degree d. We give a new proof of the fact that the automorphism group of M(r,\Lambda) is generated by automorphisms of the curve X, tensorization with suitable line bundles, and, if r divides 2d, also dualization of vector bundles.Comment: 12 page
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