Bouncing and cyclic string gas cosmologies

Abstract

We show that, in the presence of a string gas, simple higher-derivative modifications to the effective action for gravity can lead to bouncing and cyclic cosmological models. The modifications bound the expansion rate and avoid singularities at finite times. In these models the scale factors can have long loitering phases that solve the horizon problem. Adding a potential for the dilaton gives a simple realization of the pre-big bang scenario. Entropy production in the cyclic phase drives an eventual transition to a radiation-dominated universe. As a test of the Brandenberger-Vafa scenario, we comment on the probability of decompactifying three spatial dimensions in this class of models.

35 pages, LaTeX, 9 figures. v2: additional references. v3: comments on Einstein frame, version to appear in PRD

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Cited by in corpus (18)

• Towards a Resolution of the Cosmological Singularity in Non-local Higher Derivative Theories of Gravity
• Thermal Duality and Hagedorn Transition from p-adic Strings
• Thermal duality and non-singular cosmology in d-dimensional superstrings
• Thermodynamics and Cosmological Constant of Non-Local Field Theories from p-Adic Strings
• S-brane to thermal non-singular string cosmology
• Induced superstring cosmologies and moduli stabilization
• Non-singular string cosmology in a 2d Hybrid model
• Marginal Deformations of Vacua with Massive boson-fermion Degeneracy Symmetry
• The Raychaudhuri equation for a quantized timelike geodesic congruence
• Bouncing Anisotropic Universes with Varying Constants
• Quantum no-singularity theorem from geometric flows
• Dynamical Decompactification and Three Large Dimensions
• Newtonian Potential and Geodesic Completeness in Infinite Derivative Gravity
• Quantum gravity might restrict a cyclic evolution
• A bulk inflaton from large volume extra dimensions
• Bound to bounce: a coupled scalar-tachyon model for a smooth bouncing/cyclic universe
• Aspects of String Cosmology
• Antisymmetric field in string gas cosmology