Dilatonic current-carrying cosmic strings

Abstract

We investigate the nature of ordinary cosmic vortices in some scalar-tensor extensions of gravity. We find solutions for which the dilaton field condenses inside the vortex core. These solutions can be interpreted as raising the degeneracy between the eigenvalues of the effective stress-energy tensor, namely the energy per unit length U and the tension T, by picking a privileged spacelike or timelike coordinate direction; in the latter case, a phase frequency threshold occurs that is similar to what is found in ordinary neutral current-carrying cosmic strings. We find that the dilaton contribution for the equation of state, once averaged along the string worldsheet, vanishes, leading to an effective Nambu-Goto behavior of such a string network in cosmology, i.e. on very large scales. It is found also that on small scales, the energy per unit length and tension depend on the string internal coordinates in such a way as to permit the existence of centrifugally supported equilibrium configuration, also known as vortons, whose stability, depending on the very short distance (unknown) physics, can lead to catastrophic consequences on the evolution of the Universe.

10 pages, ReVTeX, 2 figures, minor typos corrected. This version to appear in Phys. Rev. D

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Cited by in corpus (7)

• Nonabelian Bosonic Currents in Cosmic Strings
• Lorentz-breaking effects in scalar-tensor theories of gravity
• Metastable gravity on classical defects
• Contributions from Dilatonic Strings to the Flat Behaviour of the Rotational Curves in Galaxies
• Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe?
• Self-Interactions in the Spacetime of a Scalar-Tensor Cosmic String
• Dilatonic, Chiral Cosmic Strings