5,758 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.
Quantum-Noise Power Spectrum of Fields with Discrete Classical Components
We present an algorithmic approach to calculate the quantum-noise spectral
density of photocurrents generated by optical fields with arbitrary discrete
classical spectrum in coherent or squeezed states. The measurement scheme may
include an arbitrary number of demodulations of the photocurrent. Thereby, our
method is applicable to the general heterodyne detection scheme which is
implemented in many experiments. For some of these experiments, e.g. in
laser-interferometric gravitational-wave detectors, a reliable prediction of
the quantum noise of fields in coherent and squeezed states plays a decisive
role in the design phase and detector characterization. Still, our
investigation is limited in two ways. First, we only consider coherent and
squeezed states of the field and second, we demand that the photocurrent
depends linearly on the field's vacuum amplitudes which means that at least one
of the classical components is comparatively strong.Comment: 8 pages, 2 figure
New perturbative solutions of the Kerr-Newman dilatonic black hole field equations
This work describes new perturbative solutions to the classical,
four-dimensional Kerr--Newman dilaton black hole field equations. Our solutions
do not require the black hole to be slowly rotating. The unperturbed solution
is taken to be the ordinary Kerr solution, and the perturbation parameter is
effectively the square of the charge-to-mass ratio of the
Kerr--Newman black hole. We have uncovered a new, exact conjugation (mirror)
symmetry for the theory, which maps the small coupling sector to the strong
coupling sector (). We also calculate the gyromagnetic ratio of
the black hole.Comment: Revtex, 27 page
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
Infinite average lifetime of an unstable bright state in the green fluorescent protein
The time evolution of the fluorescence intensity emitted by well-defined
ensembles of Green Fluorescent Proteins has been studied by using a standard
confocal microscope. In contrast with previous results obtained in single
molecule experiments, the photo-bleaching of the ensemble is well described by
a model based on Levy statistics. Moreover, this simple theoretical model
allows us to obtain information about the energy-scales involved in the aging
process.Comment: 4 pages, 4 figure
Black Extended Objects, Naked Singularities and P-Branes
We treat the horizons of charged, dilaton black extended objects as quantum
mechanical objects. We show that the S matrix for such an object can be written
in terms of a p-brane-like action. The requirements of unitarity of the S
matrix and positivity of the p-brane tension equivalent severely restrict the
number of space-time dimensions and the allowed values of the dilaton parameter
a. Generally, black objects transform at the extremal limit into p-branes.Comment: 9 pages, REVTE
BBO and the Neutron-Star-Binary Subtraction Problem
The Big Bang Observer (BBO) is a proposed space-based gravitational-wave (GW)
mission designed primarily to search for an inflation-generated GW background
in the frequency range 0.1-1 Hz. The major astrophysical foreground in this
range is gravitational radiation from inspiraling compact binaries. This
foreground is expected to be much larger than the inflation-generated
background, so to accomplish its main goal, BBO must be sensitive enough to
identify and subtract out practically all such binaries in the observable
universe. It is somewhat subtle to decide whether BBO's current baseline design
is sufficiently sensitive for this task, since, at least initially, the
dominant noise source impeding identification of any one binary is confusion
noise from all the others. Here we present a self-consistent scheme for
deciding whether BBO's baseline design is indeed adequate for subtracting out
the binary foreground. We conclude that the current baseline should be
sufficient. However if BBO's instrumental sensitivity were degraded by a factor
2-4, it could no longer perform its main mission. It is impossible to perfectly
subtract out each of the binary inspiral waveforms, so an important question is
how to deal with the "residual" errors in the post-subtraction data stream. We
sketch a strategy of "projecting out" these residual errors, at the cost of
some effective bandwidth. We also provide estimates of the sizes of various
post-Newtonian effects in the inspiral waveforms that must be accounted for in
the BBO analysis.Comment: corrects some errors in figure captions that are present in the
published versio
Old Folks and Spoiled Brats:Why the baby Boomers' Saving Crisis Need Not be that Bad
We study the impact of an anticipated "baby boom" in an overlapping generations economy.The rise of the working population lowers the wage, and the high demand for assets causes a rise in the price of capital which will be reversed when the baby boomers leave the work-force.However, the swings in factor prices are substantially dampened if we allow for more than two generations, endogenous labor supply, and convex capital adjustment costs.This is mainly due to the intertemporal shifts in labor market participation that can be observed if agents work for more than one period.Optimal saving and labor supply decisions of the baby boomers' preceding and subsequent generations partly offset the impact of the unfavorable demographic shock.Accordingly, the impact of a baby boom on the welfare of different generations crucially depends on the elasticity of labor supply
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