Brane inflation

Abstract

We present a novel inflationary scenario in theories with low scale (TeV) quantum gravity, in which the standard model particles are localized on the branes whereas gravity propagates in the bulk of large extra dimensions. This inflationary scenario is natural in the brane world picture. In the lowest energy state, a number of branes sit on top of each other (or at an orientifold plane), so the vacuum energy cancels out. In the cosmological setting, some of the branes "start out" relatively displaced in the extra dimensions and the resulting vacuum energy triggers the exponential growth of the 3 non-compact dimensions. The number of e-foldings can be very large due to the very weak brane-brane interaction at large distances. In the effective four-dimensional field theory, the brane motion is described by a slowly rolling scalar field with an extremely flat plateau potential. When branes approach each other to a critical distance, the potential becomes steep and inflation ends rapidly. Then the branes "collide" and oscillate about the equilibrium point, releasing energy mostly into radiation on the branes. Typeset using REVT E X

Brane inflation revisited after WMAP five-year results

“…3 In this case, the result of the spectral index is n s = 1.022 +0.043 −0.042 . 4 In this case, the result of the spectral index is n s = 0.968 ± 0.015. six dimensions that are compactified. The inflaton potential is given by [6,13] …”

Chiral D-brane Models with Frozen Open String Moduli

“…Of course, the absence of the latter is linked to the pattern of SUSY-breaking soft-terms which appear in the low energy effective theory, and it would be interesting to study the phenomenological consequences of such soft terms in the present model. 19 In principle, one could also think that this N = 0 flux lifts most Kähler moduli in the compactification in an indirect way. Indeed, similarly to [102,104] one could argue that the open string chiral fields participate in a D-term potential where the twisted and untwisted Kähler moduli are also involved.…”

Lumps in the throat

“…For details on this see [42]. 6 Recall that in the previous sections we have ignored the backreactions of the branes on the geometry. This is because we wanted to construct (p, q)-strings and their junctions in our 3+1-dimensional spacetime, so the backreaction effects on the internal geometry would have little effect and thus could be ignored.…”