Crossing the phantom divide barrier with scalar tensor theories
Abstract
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peer reviewed
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Journal of Cosmology and Astroparticle Physics
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Description
There is accumulating observational evidence (based on SnIa data) that the dark energy equation of state parameter w may be evolving with time and crossing the phantom divide barrier w = -1 at recent times. The con. firmation of these indications by future data would indicate that minimally coupled quintessence cannot reproduce the observed expansion rate H(z) for any scalar. eld potential. Here we explicitly demonstrate that scalar tensor theories of gravity (extended quintessence) can predict crossing of the phantom divide barrier. We reconstruct phenomenologically viable scalar-tensor potentials F(Phi) and U(Phi) that can reproduce a polynomial best fit expansion rate H(z) and the corresponding dark energy equation of state parameter w(z) crossing the w = -1 line. The form of the reconstructed scalar tensor potentials is severely constrained but is not uniquely determined. This is due to observational uncertainties in the form of H(z) and also because a single observed function H(z) does not su. ce for the reconstruction of the two potential functions F(Phi) and U(Phi).
Description
Keywords
dark energy theory, gravity, cosmology of theories beyond the sm, high-redshift supernovae, equation-of-state, cosmic background imager, hubble-space-telescope, dark energy, cosmological consequences, accelerating universe, constraints, quintessence, anisotropy
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<Go to ISI>://000233122400017
http://iopscience.iop.org/1475-7516/2005/10/001/pdf/1475-7516_2005_10_001.pdf
http://iopscience.iop.org/1475-7516/2005/10/001/pdf/1475-7516_2005_10_001.pdf
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en
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Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών