2003/11/30 by Fumikazu Koyama, Yuji Tachikawa, Taizan Watari · 74 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Dilaton #Geometry #Gravitation #Inflation (cosmology) #Inflaton #Mathematical physics #Moduli #Orientifold #Particle physics #Physics #Quantum mechanics #Singularity #Solar and Space Plasma Dynamics #String (physics) #String theory #Supergravity #Supersymmetry #Theoretical physics #astro-ph #hep-ph #hep-th
paper · pdf · open access · doi:10.1103/physrevd.69.106001
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 69(10) (American Physical Society) · 21 pages; v3. a typo corrected, and some changes made in sections 4.1 and 4.2, accordingly
openalex publication_date 2004/05/07 · arxiv created 2004/10/18 · arxiv updated 2014/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Slow-roll inflation is a beautiful paradigm, yet the inflaton potential can hardly be sufficiently flat when unknown gravitational effects are taken into account. However, the hybrid inflation models constructed in D=4, N=1 supergravity can be consistent with N=2 supersymmetry, and can be naturally embedded into string theory. This article discusses the gravitational effects carefully in the string model, using a D=4 supergravity description. We adopt the D3-D7 system of type IIB string theory compactified on a K3\ifmmode×\else\texttimes\fiT2/Z2 orientifold for definiteness. It turns out that the slow-roll parameter can be sufficiently small despite the nonminimal K"ahler potential of the model. The conditions for this to happen are given in terms of string vacua. We also find that the geometry obtained by blowing up the singularity, which is necessary for the positive vacuum energy, is stabilized by introducing certain three-form fluxes.