Bouncing and Accelerating Solutions in Nonlocal Stringy Models

Abstract

A general class of cosmological models driven by a non-local scalar field inspired by string field theories is studied. In particular cases the scalar field is a string dilaton or a string tachyon. A distinguished feature of these models is a crossing of the phantom divide. We reveal the nature of this phenomena showing that it is caused by an equivalence of the initial non-local model to a model with an infinite number of local fields some of which are ghosts. Deformations of the model that admit exact solutions are constructed. These deformations contain locking potentials that stabilize solutions. Bouncing and accelerating solutions are presented.

Minor corrections, references added, published in JHEP

References in corpus (4)

• Can dark energy evolve to the Phantom?
• New Ekpyrotic Cosmology
• Level Truncation and Rolling the Tachyon in the Lightcone Basis for Open String Field Theory
• Nonlocal String Tachyon as a Model for Cosmological Dark Energy

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• Dynamics in Nonlocal Cosmological Models Derived from String Field Theory
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• Some Lagrangians with Zeta Function Nonlocality
• Lagrangians with Riemann Zeta Function