97 research outputs found
Reconstruction of Black Hole Metric Perturbations from Weyl Curvature
Perturbation theory of rotating black holes is usually described in terms of
Weyl scalars and , which each satisfy Teukolsky's complex
master wave equation and respectively represent outgoing and ingoing radiation.
On the other hand metric perturbations of a Kerr hole can be described in terms
of (Hertz-like) potentials in outgoing or ingoing {\it radiation
gauges}. In this paper we relate these potentials to what one actually computes
in perturbation theory, i.e and . We explicitly construct
these relations in the nonrotating limit, preparatory to devising a
corresponding approach for building up the perturbed spacetime of a rotating
black hole. We discuss the application of our procedure to second order
perturbation theory and to the study of radiation reaction effects for a
particle orbiting a massive black hole.Comment: 6 Pages, Revtex
Is the brick-wall model unstable for a rotating background?
The stability of the brick wall model is analyzed in a rotating background.
It is shown that in the Kerr background without horizon but with an inner
boundary a scalar field has complex-frequency modes and that, however, the
imaginary part of the complex frequency can be small enough compared with the
Hawking temperature if the inner boundary is sufficiently close to the horizon,
say at a proper altitude of Planck scale. Hence, the time scale of the
instability due to the complex frequencies is much longer than the relaxation
time scale of the thermal state with the Hawking temperature. Since ambient
fields should settle in the thermal state in the latter time scale, the
instability is not so catastrophic. Thus, the brick wall model is well defined
even in a rotating background if the inner boundary is sufficiently close to
the horizon.Comment: Latex, 17 pages, 1 figure, accepted for publication in Phys. Rev.
Quantum Vacuum Instability Near Rotating Stars
We discuss the Starobinskii-Unruh process for the Kerr black hole. We show
how this effect is related to the theory of squeezed states. We then consider a
simple model for a highly relativistic rotating star and show that the
Starobinskii-Unruh effect is absent.Comment: 17 Pages, (accepted by PRD), (previously incorrect header files have
been corrected
Analytical treatment of SUSY Quasi-normal modes in a non-rotating Schwarzschild black hole
We use the Fock-Ivanenko formalism to obtain the Dirac equation which
describes the interaction of a massless 1/2-spin neutral fermion with a
gravitational field around a Schwarzschild black hole (BH). We obtain
approximated analytical solutions for the eigenvalues of the energy
(quasi-normal frequencies) and their corresponding eigenstates (quasi-normal
states). The interesting result is that all the excited states [and their
supersymmetric (SUSY) partners] have a purely imaginary frequency, which can be
expressed in terms of the Hawking temperature. Furthermore, as one expects for
SUSY Hamiltonians, the isolated bottom state has a real null energy eigenvalue.Comment: Version to be published in European Physical Journal
Entropy of Lovelock Black Holes
A general formula for the entropy of stationary black holes in Lovelock
gravity theories is obtained by integrating the first law of black hole
mechanics, which is derived by Hamiltonian methods. The entropy is not simply
one quarter of the surface area of the horizon, but also includes a sum of
intrinsic curvature invariants integrated over a cross section of the horizon.Comment: 15 pages, plain Latex, NSF-ITP-93-4
Black Hole Entropy without Brick Walls
We present evidence which confirms a suggestion by Susskind and Uglum
regarding black hole entropy. Using a Pauli-Villars regulator, we find that 't
Hooft's approach to evaluating black hole entropy through a
statistical-mechanical counting of states for a scalar field propagating
outside the event horizon yields precisely the one-loop renormalization of the
standard Bekenstein-Hawking formula, S=\A/(4G). Our calculation also yields a
constant contribution to the black hole entropy, a contribution associated with
the one-loop renormalization of higher curvature terms in the gravitational
action.Comment: 15 pages, plain LaTex minor additions including some references;
version accepted for publicatio
Gravity wave analogs of black holes
It is demonstrated that gravity waves of a flowing fluid in a shallow basin
can be used to simulate phenomena around black holes in the laboratory. Since
the speed of the gravity waves as well as their high-wavenumber dispersion
(subluminal vs. superluminal) can be adjusted easily by varying the height of
the fluid (and its surface tension) this scenario has certain advantages over
the sonic and dielectric black hole analogs, for example, although its use in
testing quantum effects is dubious. It can be used to investigate the various
classical instabilities associated with black (and white) holes experimentally,
including positive and negative norm mode mixing at horizons. PACS: 04.70.-s,
47.90.+a, 92.60.Dj, 04.80.-y.Comment: 14 pages RevTeX, 5 figures, section VI modifie
Noise Kernel and Stress Energy Bi-Tensor of Quantum Fields in Hot Flat Space and Gaussian Approximation in the Optical Schwarzschild Metric
Continuing our investigation of the regularization of the noise kernel in
curved spacetimes [N. G. Phillips and B. L. Hu, Phys. Rev. D {\bf 63}, 104001
(2001)] we adopt the modified point separation scheme for the class of optical
spacetimes using the Gaussian approximation for the Green functions a la
Bekenstein-Parker-Page. In the first example we derive the regularized noise
kernel for a thermal field in flat space. It is useful for black hole
nucleation considerations. In the second example of an optical Schwarzschild
spacetime we obtain a finite expression for the noise kernel at the horizon and
recover the hot flat space result at infinity. Knowledge of the noise kernel is
essential for studying issues related to black hole horizon fluctuations and
Hawking radiation backreaction. We show that the Gaussian approximated Green
function which works surprisingly well for the stress tensor at the
Schwarzschild horizon produces significant error in the noise kernel there. We
identify the failure as occurring at the fourth covariant derivative order.Comment: 21 pages, RevTeX
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
change
Psychology and aggression
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68264/2/10.1177_002200275900300301.pd
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