4,681 research outputs found

    Perturbations in the Kerr-Newman Dilatonic Black Hole Background: I. Maxwell waves

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    In this paper we analyze the perturbations of the Kerr-Newman dilatonic black hole background. For this purpose we perform a double expansion in both the background electric charge and the wave parameters of the relevant quantities in the Newman-Penrose formalism. We then display the gravitational, dilatonic and electromagnetic equations, which reproduce the static solution (at zero order in the wave parameter) and the corresponding wave equations in the Kerr background (at first order in the wave parameter and zero order in the electric charge). At higher orders in the electric charge one encounters corrections to the propagations of waves induced by the presence of a non-vanishing dilaton. An explicit computation is carried out for the electromagnetic waves up to the asymptotic form of the Maxwell field perturbations produced by the interaction with dilatonic waves. A simple physical model is proposed which could make these perturbations relevant to the detection of radiation coming from the region of space near a black hole.Comment: RevTeX, 36 pages in preprint style, 1 figure posted as a separate PS file, submitted to Phys. Rev.

    Sobolev metrics on shape space of surfaces

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    Let MM and NN be connected manifolds without boundary with dim(M)<dim(N)\dim(M) < \dim(N), and let MM compact. Then shape space in this work is either the manifold of submanifolds of NN that are diffeomorphic to MM, or the orbifold of unparametrized immersions of MM in NN. We investigate the Sobolev Riemannian metrics on shape space: These are induced by metrics of the following form on the space of immersions: G^P_f(h,k) = \int_{M} \g(P^f h, k)\, \vol(f^*\g) where \g is some fixed metric on NN, f^*\g is the induced metric on MM, h,kΓ(fTN)h,k \in \Gamma(f^*TN) are tangent vectors at ff to the space of embeddings or immersions, and PfP^f is a positive, selfadjoint, bijective scalar pseudo differential operator of order 2p2p depending smoothly on ff. We consider later specifically the operator Pf=1+AΔpP^f=1 + A\Delta^p, where Δ\Delta is the Bochner-Laplacian on MM induced by the metric fgˉf^*\bar g. For these metrics we compute the geodesic equations both on the space of immersions and on shape space, and also the conserved momenta arising from the obvious symmetries. We also show that the geodesic equation is well-posed on spaces of immersions, and also on diffeomorphism groups. We give examples of numerical solutions.Comment: 52 pages, final version as it will appea

    Microfield Dynamics of Black Holes

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    The microcanonical treatment of black holes as opposed to the canonical formulation is reviewed and some major differences are displayed. In particular the decay rates are compared in the two different pictures.Comment: 22 pages, 4 figures, Revtex, Minor change in forma

    Smooth perturbations of the functional calculus and applications to Riemannian geometry on spaces of metrics

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    We show for a certain class of operators AA and holomorphic functions ff that the functional calculus Af(A)A\mapsto f(A) is holomorphic. Using this result we are able to prove that fractional Laplacians (1+Δg)p(1+\Delta^g)^p depend real analytically on the metric gg in suitable Sobolev topologies. As an application we obtain local well-posedness of the geodesic equation for fractional Sobolev metrics on the space of all Riemannian metrics.Comment: 31 page

    Statistical mechanics of Kerr-Newman dilaton black holes and the bootstrap condition

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    The Bekenstein-Hawking ``entropy'' of a Kerr-Newman dilaton black hole is computed in a perturbative expansion in the charge-to-mass ratio. The most probable configuration for a gas of such black holes is analyzed in the microcanonical formalism and it is argued that it does not satisfy the equipartition principle but a bootstrap condition. It is also suggested that the present results are further support for an interpretation of black holes as excitations of extended objects.Comment: RevTeX, 5 pages, 2 PS figures included (requires epsf), submitted to Phys. Rev. Let

    C S Lewis- His Method and Message

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    Mr. Lewis’s real Job is being a don in the Honour School of English Language and Literature, a Tutor and Fellow at Magdalen College, Oxford, a position he has held since 1925. Bitterest opponents of his bearing a torch for Christianity say that his work in the field of literary criticism is unsurpassed. His works in this field include, “The Allegory of Love”, “Rehabilitation”, “The Personal Heresy”, and “Preface To \u27Paradise Lost’”. In the field of social theory he has written “The Abolition of Man”. In this thesis we shall concern ourselves only with the theological writings of Mr. Lewis
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