Graceful Exit in String Cosmology
نویسندگان
چکیده
The graceful exit transition from a dilaton-driven inflationary phase to a decelerated Friedmann−Robertson−Walker era requires certain classical and quantum corrections to the string effective action. Classical corrections can stabilize a high curvature string phase while the evolution is still in the weakly coupled regime, and quantum corrections can induce violation of the null energy condition, allowing evolution towards a decelerated phase. 1. Based on talk given at the workshop Modern Modified Theories of Gravitation and Cosmology, 29-30 June 1997, Ben-Gurion University, Beer-Sheva, Israel. 2. Based on talk given at the International Europhysics Conference on High Energy Physics, 19-26 August 1997, Jerusalem, Israel.
منابع مشابه
Graceful Exit and Energy Conditions in String Cosmology
String cosmology solutions are examined in a generalized phase-space including sources representing arbitrary corrections to lowest order string-dilatongravity effective action. We find a set of necessary conditions for a graceful exit transition from a dilaton-driven inflationary phase to a radiation dominated era. We show that sources allowing such a transition have to violate energy conditio...
متن کاملString Cosmology
We present a brief review of recent advances in string cosmology. Starting with the Dilaton-Moduli Cosmology (known also as the Pre Big Bang), we go on to include the effects of axion fields and address the thorny issue of the Graceful Exit in String Cosmology. This is followed by a review of density perturbations arising in string cosmology and we finish with a brief introduction to the impact...
متن کاملThe Graceful Exit in Pre-Big Bang String Cosmology
We re-examine the graceful exit problem in the pre-Big Bang scenario of string cosmology, by considering the most general time-dependent classical correction to the Lagrangian with up to four derivatives. By including possible forms for quantum loop corrections we examine the allowed region of parameter space for the coupling constants which enable our solutions to link smoothly the two asympto...
متن کاملOn Graceful Exit in String Cosmology with Pre-Big Bang Phase
We analyze the problem of graceful exit from superinflationary pre-big bang phase of string cosmology within the context of lowest-order string effective action. The previous no go theorems are generalized for the case when higher genus terms of general form and additional matter fields are included. It is shown that the choice of the E-frame essentially simplifies the consideration. For the ex...
متن کاملGraceful Exit in String Cosmology RamBrustein and RichardMadden
The graceful exit transition from a dilaton-driven inflationary phase to a decelerated Friedmann−Robertson−Walker era requires certain classical and quantum corrections to the string effective action. Classical corrections can stabilize a high curvature string phase while the evolution is still in the weakly coupled regime, and quantum corrections can induce violation of the null energy conditi...
متن کامل