A late-time transition in the cosmic dark energy?

الأصل · EN

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, zₜ, to a final negative pressure -1 < wf < -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 zₜ = 2.0⁺².²₋₀.₇₆, ΩQ = 0.73⁺⁰.⁰²₋₀.₀₄ and wf = -1⁺⁰.².