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Centro de Astrofísica da Universidade do Porto

Is w ≠ -1 evidence for a dynamical dark energy equation of state ?

P. P. Avelino, A. M. M. Trindade, P. T. P. Viana

Abstract
Current constraints on the dark energy equation of state parameter, w, are expected to be improved by more than 1 order of magnitude in the next decade. If |w−1| ≳ 0.01 around the present time, but the dark energy dynamics is sufficiently slow, it is possible that future constraints will rule out a cosmological constant while being consistent with a time-independent equation of state parameter. In this paper, we show that although models with such behavior can be constructed, they do require significant fine-tuning. Therefore, if the observed acceleration of the Universe is induced by a dark energy component, then finding w ≠ -1 would, on its own, constitute very strong evidence for a dynamical dark energy equation of state.

Physical Review D
Volume 80, Page 067302.1
September 2009

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