On the Superstrings-Induced Four-Dimensional Gravity and Its Applications to Cosmology. (16th December 2008)

• Record Type: Journal Article
• Authors: Iihoshi, Masao; Ketov, Sergei V.
• Other Names: Petkou Anastasios Academic Editor.
• Is Part Of: Advances in high energy physics. Volume 2008(2008)
• Publication Date: 2008-12-16
• Subjects: Particles (Nuclear physics) -- Periodicals; Particles (Nuclear physics); Periodicals; 539.76
• DOI: 10.1155/2008/521389
• Languages: English
• ISSNs: 1687-7357

Abstract

Abstract : We review the status of the fourth-order (quartic in the spacetime curvature) terms induced by superstrings/M-theory (compactified on a warped torus) in the leading order with respect to the Regge slope parameter, and study their (nonperturbative) impact on the evolution of the Hubble scale in the context of the four-dimensional FRW cosmology. After taking into account the quantum ambiguities in the definition of the off-shell superstring effective action, we propose the generalized Friedmann equations, find the existence of their (de Sitter) exact inflationary solutions without a spacetime singularity, and constrain the ambiguities by demanding stability and the scale factor duality invariance of our solutions. The most naive (Bel-Robinson tensor squared) quartic terms are ruled out, thus giving the evidence for the necessity of extra quartic (Ricci tensor-dependent) terms in the off-shell gravitational effective action for superstrings. Our methods are generalizable to the higher orders in the spacetime curvature.