The higher dimensional spherical symmetric scalar field collapse problem is studied in the light of the critical behavior in black hole formation. To make the analysis tractable, the self similarity is also imposed. By giving a new view to the self-similar scalar field collapse problem, we give the general formula for the critical exponents in higher dimensions. In the process, the explanation ...

A dynamical symmetry for spherical collapse has been studied using a linear transformation of the initial data set (mass and kinetic energy function) and the area radius. With proper choice of the initial area radius, the evolution as well as the physical parameters namely energy density and shear remain invariant both initially and at any time instant. Finally, it is found that the final outco...

We study the final/initial behavior of a dust Universe with spatial spherical symmetry. This study is done in proximity of the collapse/generation times by an expansion in fractional Puiseux series. Even if the evolution of the universe has different behaviours depending on the initial data (in particular on the initial spatial curvature), we show that, in proximity of generation or collapse ti...

Experimentally measured conical emission rings on the blue side of the filament supercontinuum of a 800 nm 50 fs pulse in air are reproduced in simulations with plasma and the third-order Kerr as the nonlinear terms. This agreement indicates plasma as the dominant mechanism arresting the self-focusing collapse. The higher order Kerr terms with the recently measured coefficients stop the collaps...

In this pedagogically structured article, we describe a generalized harmonic formulation of the Einstein equations in spherical symmetry which is regular at the origin. The generalized harmonic approach has attracted significant attention in numerical relativity over the past few years, especially as applied to the problem of binary inspiral and merger. A key issue when using the technique is t...

The recently published analytic probability density function for the mildly non-linear cosmic density field within spherical cells is used to build a simple but accurate maximum likelihood estimate for the redshift evolution of the variance of the density, which, as expected, is shown to have smaller relative error than the sample variance. This estimator provides a competitive probe for the eq...

Gravitational theories differing from General Relativity may explain the accelerated expansion of Universe without a cosmological constant. However, to pass local gravitational tests, "screening mechanism" is needed suppress, on small scales, fifth force driving acceleration. We consider simplest these theories, i.e. scalar-tensor theory with first-order derivative self-interactions, and study ...

nowadays, as a result of increased terrorist and bomb attacks throughout the globe in the vicinity of strategic buildings, designing these structures against impact loads, particularly the blast-related ones, has been taken into more consideration. the current procedure for designing the structure against an explosion is a design against the local failure of the current elements in the first st...

Critical collapse in general relativity refers to phenomena that occur at the threshold, in the space of initial data, between data that lead to black hole formation (collapse) and those that do not. Regular initial data can be classified as supercritical or subcritical according to whether or not they form a black hole. We refer to the boundary between supercritical and subcritical data as the...

Using a Newtonian approximation we developed a quantitative criterion for the collapse of a spherical distribution of matter under an isolated texture field. In particular, we found the evolution of an overdense region is strongly determined by two parameters: the energy scale of symmetry breaking (η) and the initial radius of the system. Applying our collapse criterion to typical galaxy scales...