Related papers: The Second Parameter Problem(s)
This paper addresses the modelling issue of the linearly-polarized solar limb spectrum, which is due to scattering processes and it offers a rich diagnostic potential for exploring solar magnetic fields via the Hanle effect. However, this…
The second-order coherence of light is a widely recognized physical quantity used to assess the quantum characteristics of light, and its properties have been extensively investigated in the field of quantum optics. Recently, it has been…
A manifestly covariant equation is derived to describe the second order perturbations in topological defects and membranes on arbitrary curved background spacetimes. This, on one hand, generalizes work on macroscopic strings in Minkowski…
In the early seventies, Alan Sandage defined cosmology as the search for two numbers: Hubble parameter ${{H}_{0}}$ and deceleration parameter ${{q}_{0}}$. The first of the two basic cosmological parameters (the Hubble parameter) describes…
Despite encouraging recent progresses in ensemble approaches, classification methods seem to have reached a plateau in development. Further advances depend on a better understanding of geometrical and topological characteristics of point…
We analytically investigate the effect of a non-centrosymmetric geometry in the optical second harmonic (SH) generation from a particle made of a centrosymmetric material, in the interior of which quadratic optical processes are suppressed.…
The secular evolution process, which slowly transforms the morphology of a galaxy over its lifetime, could naturally account for observed properties of the great majority of physical galaxies if both stellar and gaseous accretion processes…
A general method is described for detecting and analysing galaxy systems. The multivariate geometrical structure of the sample is studied by using an extension of the method which we introduced in a previous paper. The method is based on an…
A scenario with two subsequent periods of inflationary expansion in the very early universe is examined. The model is based on a potential motivated by symmetries being found in field theory at high energy. For various parameter sets of the…
In this essay, we discuss the fine-tuning problems of the Higgs mass and the cosmological constant. We argue that these are indeed legitimate problems, as opposed to some other "problems" that are sometimes described using similar…
The role of $SL(2,IR)$ symmetry in two-dimensional gravity is investigated in the context of the extended hamiltonian formalism. Using our results we clarify previous works on the subject.
Principal component method is used to study galactic globular clusters in 7- and 8-axis space of structural parameters. It is shown that the manifold properties of clusters with this set of parameters is determined mainly by two independent…
Accounting for all the relativistic effects, we have developed the fully nonlinear gauge-invariant formalism for describing the cosmological observables and presented the second-order perturbative expressions associated with light…
The paper studies the complex differentiable functions of double argument and their properties, which are similar to the properties of the holomorphic functions of complex variable: the Cauchy formula, the hyperbolic harmonicity, the…
A revival over the past two decades in planetary nebula (PN) morphological studies springs from a combination of factors, including the advent of wide-area, high dynamic range detectors; the growing archives of high resolution images from…
Modern ab initio treatments of H-Hbar systems are inconsistent with the logic behind algebraic Hamiltonians H(+-)=H(0)+/-deltaH for charge-symmetrical and charge-asymmetrical 4 unit charge systems like H(2) and HHbar. Since these 2…
Second-order superintegrable systems in dimensions two and three are essentially classified. With increasing dimension, however, the non-linear partial differential equations employed in current methods become unmanageable. Here we propose…
We explore the use of galaxy bispectrum induced by the nonlinear gravitational evolution as a possible probe to test general scalar-tensor theories with second-order equations of motion. We find that time dependence of the leading…
It has recently been reported that the application of convolutional neural-network techniques to infer the dark-matter distribution in the local cosmos has revealed how it follows the $D\approx 2$ hierarchical distribution of galaxies in…
The Hamilton-Jacobi problem is revisited bearing in mind the consequences arising from a possible bi-Hamiltonian structure. The problem is formulated on the tangent bundle for Lagrangian systems in order to avoid the bias of the existence…