Cosmology from string theory

String Theory and Cosmology

We discuss the main cosmological implications of considering string-loop eeects and a potential for the dilaton in the lowest order string eeective action. Our framework is based on the eeective model arising from regarding homogeneous and isotropic dilaton, metric and Yang-Mills eld conngurations. The issues of innation, entropy crisis and the Polonyi problem as well as the problem of the cosm...

Lectures on string theory and cosmology

In these lectures I review recent attempts to apply string theory to cosmology, including string cosmology and various models of brane cosmology. In addition, the review includes an introduction to inflation as well as a discussion of transplanckian signatures. I also provide a critical discussion of the possible role of holography. The material is based on lectures given in January 2004 at the...

DEVELOPMENT IN STRING THEORY

The string theory is a fast moving subject, both physics wise and in the respect of mathematics. In order to keep up with the discipline it is important to move with new ideas which are being stressed. Here I wish to give extracts from new papers of ideas which I have recently found interesting. There are six papers which are involved: I ."Strings formulated directly in 4 dimensions " A. N...

superstring scatterng from dbranes and wess zumino terms in string theory

دو هدف را برای انجام این پایان نامه دنبال می کنیم . نشان می دهیم که بسط دامنه پراکندگی یک میدان راموند-راموند دو میدان پیمانه ای و یک میدان تاکیونی caat بسط سازگاری است که این نکته بیانگر آنست که بسط تاکیونها که بسط انرژی پایین نیست را یافته ایم و این بسط با بسط aatt,ctta,cta,cttt سازگار است با مقایسه با دامنه پراکندگی تعدادی از تصحیحات کنشهای tachyonic dbi, wess-zumino را می یابیم .

String Cosmology