Antisymmetric-Tensor and Electromagnetic effects in an alpha'-non-perturbative Four-Dimensional String Cosmology

Abstract

Starting from an exact (in the Regge slope alpha') functional method for a bosonic stringy sigma-model, we investigate four-dimensional cosmological string solutions in graviton, dilaton and antisymmetric tensor backgrounds, compatible with world-sheet conformal invariance, and valid beyond perturbative expansions in powers of alpha'. The antisymmetric tensor field, playing the role of an axion in the four-dimensional target space time, leads to spatial anisotropies of the emergent Robertson-Walker expanding Universe, and, upon coupling the system to the electromagnetic field, it results in non-trivial optical activity. Some estimates of the corresponding effects are made and their relevance to current cosmology is briefly discussed.

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Cited by in corpus (8)

• Magnetic monopoles revisited: Models and searches at colliders and in the Cosmos
• Magnetic Monopoles from Global Monopoles in the presence of Kalb-Ramond Torsion
• Environmental CPT Violation in an Expanding Universe in String Theory
• Kalb-Ramond backgrounds in ${\alpha }^{\prime }$-complete cosmology
• Non-perturbative time-dependent String Backgrounds and Axion-induced Optical Activity
• Tachyon-Dilaton-induced Inflation as an alpha'-resummed String Background
• Non-renormalization for the Liouville wave function
• Dark Energy as an off-shell Tachyon Background in four-dimensional Strings