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 $(Q/M)^2$ 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 ($\phi \to -\phi$). We also calculate the gyromagnetic ratio of the black hole.Comment: Revtex, 27 page

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

Theoretical survey of tidal-charged black holes at the LHC

We analyse a family of brane-world black holes which solve the effective four-dimensional Einstein equations for a wide range of parameters related to the unknown bulk/brane physics. We first constrain the parameters using known experimental bounds and, for the allowed cases, perform a numerical analysis of their time evolution, which includes accretion through the Earth. The study is aimed at predicting the typical behavior one can expect if such black holes were produced at the LHC. Most notably, we find that, under no circumstances, would the black holes reach the (hazardous) regime of Bondi accretion. Nonetheless, the possibility remains that black holes live long enough to escape from the accelerator (and even from the Earth's gravitational field) and result in missing energy from the detectors.Comment: RevTeX4, 12 pages, 4 figures, 5 tables, minor changes to match the accepted version in JHE

Coloration in the polymorphic frog Oophaga pumilio associates with level of aggressiveness in intraspecific and interspecific behavioral interactions

© 2015, Springer-Verlag Berlin Heidelberg. Intraspecific morphological variation may correspond to behavioral variation that helps determine the nature of species interactions. Color variation among populations of variably toxic organisms has been shown to associate with alternative anti-predator behaviors. However, the effects of these alternative behavioral tendencies on the outcomes of interspecific interactions other than predator–prey remain largely unexplored. We investigated how coloration and body size variation in Oophaga pumilio, one of the most phenotypically diverse amphibians known, associated with territorial aggressiveness and how this association influenced the outcome of agonistic male–male interactions with conspecifics and heterospecifics of two sympatric species (Andinobates claudiae and Phyllobates lugubris). Irrespective of body size, resident frogs from more conspicuous, red-colored O. pumilio populations responded to same-morph conspecifics and P. lugubris more quickly and exhibited more aggressive behaviors and more energetically expensive behaviors than resident frogs from green populations under these same treatments. Furthermore, red-colored resident frogs dominated most of the interactions in which they were involved, whereas green residents dominated only a few of the interactions, despite their status as residents. Because conspecific and heterospecific intruders did not behave more aggressively toward red resident frogs, aggressiveness of red residents does not appear to be a response to higher aggression being directed toward them. These results suggest that coloration in O. pumilio is a good indicator of aggressiveness that associates with the outcome of intraspecific and some interspecific behavioral male–male interactions, providing support for a positive association among anti-predator traits, agonistic behavior, and dominance in both intraspecific and interspecific, intraguild interactions

Simulation of underground gravity gradients from stochastic seismic fields

We present results obtained from a finite-element simulation of seismic displacement fields and of gravity gradients generated by those fields. The displacement field is constructed by a plane wave model with a 3D isotropic stochastic field and a 2D fundamental Rayleigh field. The plane wave model provides an accurate representation of stationary fields from distant sources. Underground gravity gradients are calculated as acceleration of a free test mass inside a cavity. The results are discussed in the context of gravity-gradient noise subtraction in third generation gravitational-wave detectors. Error analysis with respect to the density of the simulated grid leads to a derivation of an improved seismometer placement inside a 3D array which would be used in practice to monitor the seismic field.Comment: 24 pages, 12 figure