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A late-time transition in the cosmic dark energy?

Bruce A. Bassett·Martin Kunz·Joseph Silk·Carlo Ungarelli
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Abstract

We study constraints from the latest CMB, large scale structure (2dF, Abell/ACO, PSCz) and SN1a data on dark energy models with a sharp transition in their equation of state, w(z). Such a transition is motivated by models like vacuum metamorphosis where non-perturbative quantum effects are important at late times. We allow the transition to occur at a specific redshift, z_t, to a final negative pressure -1 < w_f < -1/3. We find that the CMB and supernovae data, in particular, prefer a late-time transition due to the associated delay in cosmic acceleration. The best fits (with 1 sigma errors) to all the data are z_t = 2.0^{+2.2}_{-0.76}, Ω_Q = 0.73^{+0.02}_{-0.04} and w_f = -1^{+0.2}.

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Bruce A. Bassett, Martin Kunz, Joseph Silk, Carlo Ungarelli. 2002-03-21. A late-time transition in the cosmic dark energy?. https://doi.org/10.1046/j.1365-8711.2002.05887.x

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