On the line shape of the total rovibronic absorption in laser-dressed diatomic molecules

Recently, the rovibronic absorption and emission spectra of diatomic molecules dressed by medium-intensity laser fields have been discussed. By computing the total absorption probability as a function of dressing wavelength an asymmetric line shape has been obtained strongly resembling to the well-known Fano line shape. Applying two-state analytical and three-state numerical models the shape of the total absorption probability function is explained. Further confirmation of the model based results is provided by high resolution accurate numerical computations using large number of basis functions.

Methodology and algorithm to correct the thermal neutron porosity for the effect of rare elements and rock minerals with high neutron absorption probability

The thermal neutron porosity is routinely acquired in almost every well. When combined with the density, gamma ray and resistivity logs, the basic petrophysical parameters of a reservoir are evaluated. The design of the thermal neutron tool is simple, but its interpretation is complex and affected by the formation constituents. The most challenging situation occurs when the formation contains elements with high absorption probability of the thermal neutrons. The existence of such elements changes the neutron transport parameters and results in a false increase in the measured porosity. The problem is reported by many users throughout the years. In 1993, higher thermal neutron porosity is reported due to the existence of an iron-rich mineral, Siderite, in the Nazzazat and Baharia formations in Egypt. Siderite and all iron-rich minerals have high thermal neutrons absorption probability. Recently, in 2018, high thermal neutron porosity in Unayzah field in Saudi Arabia is also reported due to the existence of few parts per million of gadolinium. Gadolinium is a rare element that has high probability of thermal neutron absorption. Currently, none of the existing commercial petrophysics software(s) have modules to correct the thermal neutron porosity for such effects. This represents a challenge to the petrophysicists to properly calculate the actual reservoir porosity. In this paper, the effects of the rare elements and other minerals with high thermal neutron absorption probability on the thermal neutron porosity are discussed, and a correction methodology is developed and tested. The methodology is based on integrating the tool design and the physics of the neutron transport to perform the correction. The details of the correction steps and the correction algorithm are included, tested and applied in two fields.

The variational method, backreactions, and the absorption probability in Wald type problems

We argue that the variational method in Wald type thought experiments, involves order of magnitude problems when one imposes the fact that $$\delta M$$ δ M is inherently a first order quantity itself. One observes that the contribution of the second order perturbations is actually of the fourth order. Therefore backreactions have to be explicitly calculated. Here, we re-consider the overspinning problem for Kerr–Newman black holes interacting with test fields. We calculate the backreaction effects due to the induced increase in the angular velocity of the event horizon, which brings a partial solution to the overspinning problem. To bring an ultimate solution, we argue that the absorption probability should be taken into account in Wald type problems where black holes interact with test fields. This fundamentally alters the course of the analysis of the thought experiments. Due to the fact that a small fraction of the challenging modes is absorbed by the black holes, overspinning is prevented for both nearly extremal and extremal cases. Some extreme cases are easily fixed by backreaction effects. The arguments do not apply to the generic overspinning by fermionic fields for which the absorption probability is positive definite.

Bereichsspezifische Strategien im Stochastiksunterricht

For multi-stage random experiments, probability trees are used for their description. Using the path rules, probabilities for the results of such multi-level experiments can be calculated from the probabilities that characterize the transitions from one step to the next. A natural next step is to look for sequences of random experiments, which can be represented by directed graphs. Analogous to the path rules, mean value rules serve to determine probabilities for an end of these random processes and their expected durations. Directed graphs and mean rules represent domain-specific strategies that take up and develop concepts of stochastic teaching at secondary level. Classification: D54, K64, N74, D29. Keywords: stochastics education, stochastically thinking, domain-specific strategy, MARKOV chains, directed graph, absorption probability, mean hitting time, transition probabilities, “Mittelwertsregeln”.

Novel Perceptually Uniform Chromatic Space

Chromatically perceptive observers are endowed with a sense of similarity between colors. For example, two shades of green that are only slightly discriminable are perceived as similar, whereas other pairs of colors, for example, blue and yellow, typically elicit markedly different sensations. The notion of similarity need not be shared by different observers. Dichromat and trichromat subjects perceive colors differently, and two dichromats (or two trichromats, for that matter) may judge chromatic differences inconsistently. Moreover, there is ample evidence that different animal species sense colors diversely. To capture the subjective metric of color perception, here we construct a notion of distance in color space based on the physiology of the retina, and is thereby individually tailored for different observers. By applying the Fisher metric to an analytical model of color representation, we construct a notion of distance that reproduces behavioral experiments of classical discrimination tasks. We then derive a coordinate transformation that defines a new chromatic space in which the Euclidean distance between any two colors is equal to the perceptual distance, as seen by one individual subject, endowed with an arbitrary number of color-sensitive photoreceptors, each with arbitrary absorption probability curves and appearing in arbitrary proportions.

White holes as the asymptotic limit of evaporating primordial black holes

This paper examines the interaction of an intense fermion field with all of the particle species of an attometer primordial black hole’s (PBH) high energy Hawking radiation spectrum. By extrapolating to Planck-sized PBHs, it is shown that although Planck-sized PBHs closely simulate the zero absorption requirement of white holes, the absorption probability is not truly zero, and therefore, thermodynamically, Planck-sized primordial black holes are not true white holes.

SCATTERING OF SCALAR PERTURBATIONS WITH COSMOLOGICAL CONSTANT IN LOW-ENERGY AND HIGH-ENERGY REGIMES

We study the absorption and scattering of massless scalar waves propagating in spherically symmetric spacetimes with dynamical cosmological constant both in low-energy and high-energy zones. In the former low-energy regime, we solve analytically the Regge–Wheeler wave equation and obtain an analytic absorption probability expression which varies with [Formula: see text], where M is the central mass and Λ is cosmological constant. The low-energy absorption probability, which is in the range of [0, 0.986701], increases monotonically with increase in Λ. In the latter high-energy regime, the scalar particles adopt their geometric optics limit value. The trajectory equation with effective potential emerges and the analytic high-energy greybody factor, which is relevant with the area of classically accessible regime, also increases monotonically with increase in Λ, as long Λ is less than or of the order of 104. In this high-energy case, the null cosmological constant result reduces to the Schwarzschild value [Formula: see text].