On the superstrings-induced four-dimensional gravity, and its applications to cosmology

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 (non-perturbative) 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.

33 pages, LaTeX, no figures; extensive revision, Sec.6 and references added, stability analysis included

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Cited by in corpus (10)

• Superstring-inspired supergravity as the universal source of inflation and quintessence
• Fourth-order gravity as the inflationary model revisited
• On the superstring-inspired quantum correction to the Starobinsky model of inflation
• Slow-roll inflation in (R+R*4) gravity
• F(R) supergravity
• Scalar potential in F(R) supergravity
• Stability investigations of isotropic and anisotropic exponential inflation in the Starobinsky-Bel-Robinson gravity
• Starobinsky inflation beyond the leading order
• Einstein-Grisaru-Zanon gravity
• Starobinsky-Bel-Robinson gravity