1,622 research outputs found

    Topological geon black holes in Einstein-Yang-Mills theory

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    We construct topological geon quotients of two families of Einstein-Yang-Mills black holes. For Kuenzle's static, spherically symmetric SU(n) black holes with n>2, a geon quotient exists but generically requires promoting charge conjugation into a gauge symmetry. For Kleihaus and Kunz's static, axially symmetric SU(2) black holes a geon quotient exists without gauging charge conjugation, and the parity of the gauge field winding number determines whether the geon gauge bundle is trivial. The geon's gauge bundle structure is expected to have an imprint in the Hawking-Unruh effect for quantum fields that couple to the background gauge field.Comment: 27 pages. v3: Presentation expanded. Minor corrections and addition

    Resilience is paramount for managing socio-technological systems during and post-Covid-19

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    The spread of the coronavirus concomitant with the Covid-19 disease highlights the interconnectedness between systems that serve humanity. These systems are typically portrayed in economic, ecology and environment, physical/technological, and socio-political contexts and maybe delineated in terms of the interconnectedness between these contexts. Any delineated socio-technological system represents an intriguing class of interconnected systems in the novel era of Society 5.0 concomitant with fourth industrial revolution. This article describes a framework and resiliency model for socio-technological systems plus an application of the lens of vulnerability and resilience to a case study energy systems enterprise. It is intriguing that the energy systems enterprise is usurping extant socio-economic robustness thereby undergoing an absorptive phase of resilience. The discourse complements existing body of literature on energy systems and society by emphasizing that the principles of vulnerability and resilience are paramount for sustainable management of socio-technological systems, and more so in a post-Covid-19 world.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp/?punumber=46hj2021Graduate School of Technology Management (GSTM

    The Imprint of Gravitational Waves on the Cosmic Microwave Background

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    Long-wavelength gravitational waves can induce significant temperature anisotropy in the cosmic microwave background. Distinguishing this from anisotropy induced by energy density fluctuations is critical for testing inflationary cosmology and theories of large-scale structure formation. We describe full radiative transport calculations of the two contributions and show that they differ dramatically at angular scales below a few degrees. We show how anisotropy experiments probing large- and small-angular scales can combine to distinguish the imprint due to gravitational waves.Comment: 11 pages, Penn Preprint-UPR-

    Coset Space Dimensional Reduction and Wilson Flux Breaking of Ten-Dimensional N=1, E(8) Gauge Theory

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    We consider a N=1 supersymmetric E(8) gauge theory, defined in ten dimensions and we determine all four-dimensional gauge theories resulting from the generalized dimensional reduction a la Forgacs-Manton over coset spaces, followed by a subsequent application of the Wilson flux spontaneous symmetry breaking mechanism. Our investigation is constrained only by the requirements that (i) the dimensional reduction leads to the potentially phenomenologically interesting, anomaly free, four-dimensional E(6), SO(10) and SU(5) GUTs and (ii) the Wilson flux mechanism makes use only of the freely acting discrete symmetries of all possible six-dimensional coset spaces.Comment: 45 pages, 2 figures, 10 tables, uses xy.sty, longtable.sty, ltxtable.sty, (a shorter version will be published in Eur. Phys. J. C

    A New Class of Exact Hairy Black Hole Solutions

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    We present a new class of black hole solutions with minimally coupled scalar field in the presence of a negative cosmological constant. We consider a one-parameter family of self-interaction potentials parametrized by a dimensionless parameter gg. When g=0g=0, we recover the conformally invariant solution of the Martinez-Troncoso-Zanelli (MTZ) black hole. A non-vanishing gg signals the departure from conformal invariance. All solutions are perturbatively stable for negative black hole mass and they may develop instabilities for positive mass. Thermodynamically, there is a critical temperature at vanishing black hole mass, where a higher-order phase transition occurs, as in the case of the MTZ black hole. Additionally, we obtain a branch of hairy solutions which undergo a first-order phase transition at a second critical temperature which depends on gg and it is higher than the MTZ critical temperature. As g→0g\to 0, this second critical temperature diverges.Comment: 18 pages, 6 figures, minor changes, references added, published versio

    Equidistribution of zeros of holomorphic sections in the non compact setting

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    We consider N-tensor powers of a positive Hermitian line bundle L over a non-compact complex manifold X. In the compact case, B. Shiffman and S. Zelditch proved that the zeros of random sections become asymptotically uniformly distributed with respect to the natural measure coming from the curvature of L, as N tends to infinity. Under certain boundedness assumptions on the curvature of the canonical line bundle of X and on the Chern form of L we prove a non-compact version of this result. We give various applications, including the limiting distribution of zeros of cusp forms with respect to the principal congruence subgroups of SL2(Z) and to the hyperbolic measure, the higher dimensional case of arithmetic quotients and the case of orthogonal polynomials with weights at infinity. We also give estimates for the speed of convergence of the currents of integration on the zero-divisors.Comment: 25 pages; v.2 is a final update to agree with the published pape

    Dental Caries Experience in the Deciduous Dentition of Rural Guatemalan Children Ages 6 Months to 7 Years

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    A study of 528 Guatemalan children indicated that caries prevalence in the deciduous dentition was twice as great as but in the permanent dentition was similar to that for US white children. This is a repeated observation for children of some preindustrial societies. Caries experience was significantly greater in boys. Until 4 years of age, caries attack was greater in the anterior segment of the oral cavity; linear enamel hypoplasia was a predisposing factor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68238/2/10.1177_00220345760550064501.pd

    Multi-dimensional gyrokinetic parameter studies based on eigenvalue computations

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    Plasma microinstabilities, which can be described in the framework of the linear gyrokinetic equations, are routinely computed in the context of stability analyses and transport predictions for magnetic confinement fusion experiments. The GENE code, which solves the gyrokinetic equations, has been coupled to the SLEPc package for an efficient iterative, matrix-free, and parallel computation of rightmost eigenvalues. This setup is presented, including the preconditioner which is necessary for the newly implemented Jacobi-Davidson solver. The fast computation of instabilities at a single parameter set is exploited to make parameter scans viable, that is to compute the solution at many points in the parameter space. Several issues related to parameter scans are discussed, such as an efficient parallelization over parameter sets and subspace recycling. © 2011 Elsevier B.V. All rights reserved.E. Romero and J.E. Roman were supported by the Spanish Ministry of Science and Innovation (MICINN) under project number TIN2009-07519.Merz, F.; Kowitz, C.; Romero Alcalde, E.; Román Moltó, JE.; Jenko, F. (2012). Multi-dimensional gyrokinetic parameter studies based on eigenvalue computations. Computer Physics Communications. 183(4):922-930. https://doi.org/10.1016/j.cpc.2011.12.018S922930183
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