منابع مشابه
Graceful Exit in String Cosmology
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 کاملGraceful Exit in Quantum String Cosmology
We write an O(d, d)-covariant Wheeler-De Witt equation in the (d + 1)-dimensional minisuperspace of low-energy cosmological string backgrounds. We discuss explicit examples of transitions between two duality-related cosmological phases, and we find a finite quantum transition probability even when the two phases are classically separated by a curvature singularity. This quantum approach is comp...
متن کاملAxions and the Graceful Exit Problem in String Cosmology
We reexamine the graceful exit problem in the Pre-Big-Bang inflationary scenario. The dilaton-gravity action is generalized by adding the axion and a general axion/dilaton potential. We provide a phase space analysis of the dynamics which leads us to extend the previous no-go theorem and rule out the branch change necessary for graceful exit in this context. Submitted to Physics Letters B
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 کاملGraceful 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...
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ژورنال
عنوان ژورنال: Journal of High Energy Physics
سال: 2000
ISSN: 1029-8479
DOI: 10.1088/1126-6708/2000/01/035