4,681 research outputs found
Perturbations in the Kerr-Newman Dilatonic Black Hole Background: I. Maxwell waves
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
Let and be connected manifolds without boundary with , and let compact. Then shape space in this work is either the
manifold of submanifolds of that are diffeomorphic to , or the orbifold
of unparametrized immersions of in . 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 , f^*\g is the
induced metric on , are tangent vectors at to
the space of embeddings or immersions, and is a positive, selfadjoint,
bijective scalar pseudo differential operator of order depending smoothly
on . We consider later specifically the operator , where
is the Bochner-Laplacian on induced by the metric . 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
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
We show for a certain class of operators and holomorphic functions
that the functional calculus is holomorphic. Using this result
we are able to prove that fractional Laplacians depend real
analytically on the metric 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
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
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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