2006/08/21 by Xingang Chen, Sash Sarangi, S. -H. Henry Tye +2 · 3 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2006/11/015
published as JCAP0611:015,2006 · 32 pages; v2: references and comments added
arxiv created 2006/08/21 · openalex publication_date 2006/11/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
In this paper, we show that eternal inflation of the random walk type is generically absent in the brane inflationary scenario. Depending on how the brane inflationary universe originated, eternal inflation of the false vacuum type is still quite possible. Since inflaton is the position of the D 3-brane relative to the 3-brane inside the compactified bulk with finite size, its value is bounded. In DBI inflation, the warped space also restricts the amplitude of the scalar fluctuation. These upper bounds impose strong constraints on the possibility of eternal inflation. We find that eternal inflation due to the random walk of the inflaton field is absent in both the KKLMMT slow-roll scenario and the DBI scenario. A more careful analysis for the slow-roll case is also presented using the Langevin equation, which gives very similar results. We discuss possible ways to obtain eternal inflation of the random walk type in brane inflation. In the multi-throat brane inflationary scenario, the branes may be generated by quantum tunnelling and roll out the throat. Eternal inflation of the false vacuum type inevitably happens in this scenario due to the tunnelling process. Since these scenarios have different cosmological predictions, more data from the cosmic microwave background radiation will hopefully select the specific scenario our universe has gone through.