2,242 research outputs found
Brane World in a Topological Black Hole Bulk
We consider a static brane in the background of a topological black hole, in
arbitrary dimensions. For hyperbolic horizons, we find a solution only when the
black hole mass assumes its minimum negative value. In this case, the tension
of the brane vanishes, and the brane position coincides with the location of
the horizon. For an elliptic horizon, we show that the massless mode of
Randall-Sundrum is recovered in the limit of large black hole mass.Comment: Latex, 8 pages, v2: Additional references, to appear in MPL
Neurophysiology
Contains reports on three research projects.National Institutes of Health (Training Grant 5 TO1 EY00090)Bell Laboratories (Grant
Quantum Creation of Topological Black Hole
The constrained instanton method is used to study quantum creation of a
vacuum or charged topological black hole. At the level, the relative
creation probability is the exponential of a quarter sum of the horizon areas
associated with the seed instanton.Comment: Report-no change onl
The binary black-hole problem at the third post-Newtonian approximation in the orbital motion: Static part
Post-Newtonian expansions of the Brill-Lindquist and Misner-Lindquist
solutions of the time-symmetric two-black-hole initial value problem are
derived. The static Hamiltonians related to the expanded solutions, after
identifying the bare masses in both solutions, are found to differ from each
other at the third post-Newtonian approximation. By shifting the position
variables of the black holes the post-Newtonian expansions of the three metrics
can be made to coincide up to the fifth post-Newtonian order resulting in
identical static Hamiltonians up the third post-Newtonian approximation. The
calculations shed light on previously performed binary point-mass calculations
at the third post-Newtonian approximation.Comment: LaTeX, 9 pages, to be submitted to Physical Review
General K=-1 Friedman-Lema\^itre models and the averaging problem in cosmology
We introduce the notion of general K=-1 Friedman-Lema\^itre (compact)
cosmologies and the notion of averaged evolution by means of an averaging map.
We then analyze the Friedman-Lema\^itre equations and the role of gravitational
energy on the universe evolution. We distinguish two asymptotic behaviors:
radiative and mass gap. We discuss the averaging problem in cosmology for them
through precise definitions. We then describe in quantitative detail the
radiative case, stressing on precise estimations on the evolution of the
gravitational energy and its effect in the universe's deceleration. Also in the
radiative case we present a smoothing property which tells that the long time
H^{3} x H^{2} stability of the flat K=-1 FL models implies H^{i+1} x H^{i}
stability independently of how big the initial state was in H^{i+1} x H^{i},
i.e. there is long time smoothing of the space-time. Finally we discuss the
existence of initial "big-bang" states of large gravitational energy, showing
that there is no mathematical restriction to assume it to be low at the
beginning of time.Comment: Revised version. 32 pages, 1 figur
Role of immediate reconstruction for elderly breast cancer patients
With rising numbers of elderly women developing breast cancer, treatment options must evolve which take into consideration quality of life and functional status. Although fewer women at all ages are undergoing mastectomy, for those elderly women who undergo mastectomy, reconstruction options should be offered. Over the past 5 years, increasing numbers of elderly women are electing immediate reconstruction (IM)
Estimates of the total gravitation radiation in the head-on black hole collision
We report on calculations of the total gravitational energy radiated in the
head-on black hole collision, where we use the geometry of the
Robinson-Trautman metrics.Comment: 10 pages, 2 figures, LaTeX2
Gravitational wave detectors based on matter wave interferometers (MIGO) are no better than laser interferometers (LIGO)
We show that a recent claim that matter wave interferometers have a much
higher sensitivity than laser interferometers for a comparable physical setup
is unfounded. We point out where the mistake in the earlier analysis is made.
We also disprove the claim that only a description based on the geodesic
deviation equation can produce the correct physical result. The equations for
the quantum dynamics of non-relativistic massive particles in a linearly
perturbed spacetime derived here are useful for treating a wider class of
related physical problems. A general discussion on the use of atom
interferometers for the detection of gravitational waves is also provided.Comment: 16 pages, REVTeX4; minor changes, one figure and a few references
were added, an additional appendix was included where we explain why,
contrary to the claims in gr-qc/0409099, the effects due to the reflection
off the mirrors cancel out in the final result for the phase shif
Fate of Kaluza-Klein Bubble
We numerically study classical time evolutions of Kaluza-Klein bubble
space-time which has negative energy after a decay of vacuum. As the zero
energy Witten's bubble space-time, where the bubble expands infinitely, the
subsequent evolutions of Brill and Horowitz's momentarily static initial data
show that the bubble will expand in terms of the area. At first glance, this
result may support Corley and Jacobson's conjecture that the bubble will expand
forever as well as the Witten's bubble. The irregular signatures, however, can
be seen in the behavior of the lapse function in the maximal slicing gauge and
the divergence of the Kretchman invariant. Since there is no appearance of the
apparent horizon, we suspect an appearance of a naked singularity as the final
fate of this space-time.Comment: 13 pages including 10 figures, RevTeX, epsf.sty. CGPG-99/12-8,
RESCEU-6/00 and DAMTP-2000-30. To appear in Phys. Rev.
Neurophysiology
Contains reports on five research projects.National Institutes of Health (Training Grant 5 TO1 EY00090)Bell Laboratories (Grant
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