Evolution of Bulk Scale Factor in Warped Space-time

In this work the role of extra dimensions in the accelerated universe through the scenario of higher-dimensional Friedmann-Robertson-Walker (FRW) cosmology has been studied. For this purpose, we first consider warped space-time in the standard flat brane scenario as the modified form of Robertson-Walker (RW) metric in five-dimension (5D) space-time and then the variation of the bulk scale factor (warp factor), with respect to both space-like and time-like extra dimensions is obtained. Finally, it is shown that both of two types of extra dimensions are important in this scenario and also the bulk scale factor plays two different roles.Comment: This paper has been withdrawn by the author due to text overlap with arXiv:0710.3790 by other author

Trans-Planckian Scale and Krein Space Quantization

In this work, Krein space quantization method is applied to eliminate the Ultraviolet divergence of Green functions. This paper shows that the power spectrum of scalar field fluctuations can be calculated in the limit of short distance physics, trans-Planckian physics, without using the usual re-normalization process.Comment: 5 pages, published in IJT

Particle Creation and Excited-de Sitter Modes

Recently, in Ref.\cite{moh1}, we introduced exited-de Sitter modes to study the power spectrum which was finite in Krein space quantization and the trans-Plankian corrections due to the exited modes were non-linear. It was shown that the de Sitter limit of corrections reduces to what obtained via the several previous conventional methods, moreover, with such modes the space-time symmetry becomes manifest. In this paper, inspired by Krein method and using exited-de Sitter modes as the fundamental initial states during the inflation, we calculate particle creation in the spatially flat Robertson-Walker space-time. It is shown that in de Sitter and Minkowski space-time in the far past time limit, our results coincides to the standard results.Comment: 8 page

Quasi-de Sitter Solution, Negative Norm State and Krein Space in Cosmology

Recent observational data have shown two important results about cosmic inflation: First, the primordial power spectrum is approximately scale invariant. Secondly, the space-time geometry during inflation is quasi-de Sitter. In this paper, we study the background field method and the concept of negative norm states in the framework of Krein space to use in early universe cosmology. For the inflaton field equation, based on the observations and taking into account our studies, we suggest an alternative proposal. We will take the quasi-de Sitter solutions as the physical geometry with the positive norm and the pure de Sitter solutions as the background geometry with the negative norm. In the following, we review the consequences of applying the proposal to calculate some cosmological quantities.Comment: 12 Page

The role of economic and legal factors in the emergence of the street children phenomenon in Khorram Abad, Lorestan province: survey in 2015

In this research, we have studied the population of street children in Khorram Abad in Iran, in 2015, with the emphasis on the role of economic and legal factors forcing children to work on the streets. The results of this research show that the issue of child labor is the consequence of both global and local matters. These children are the products of the urban society, poverty, and cultural, legal, and local factors. The research method is a survey, and the statistical population is the street children, aged between 7 to 18 living in Khorram Abad, in 2015. The sample population chosen randomly includes 242 people, and the required information was gathered using the questionnaire and interview technique. In Khorram Abad, Lorestan, economic crisis and parents' misdemeanor are the two main factors that force the children to fill their fathers' missing place by working in the streets. But, gender factors such as being a boy, and cultural factors such as belonging to a specific tribe are influential in the howness of this phenomenon. In this article, we have attempted to use native sources for a better understanding of the local situation of the phenomenon, and have proposed a few solutions to alter the current situation

Spectrum of Gravitational Waves in Krein Space Quantization

The main goal of this paper is to derive the primordial power spectrum for the scalar perturbations generated as a result of quantum fluctuations during an inflationary pe- riod by an alternative approach of field quantization[1-3]. Formulas are derived for the gravitational waves, special cases of which include power law inflation and inflation in the slow roll approximation, in Krein space quantization.Comment: 6 pages, published in MPL