https://doi.org/10.1140/epjc/s10052-011-1735-x
Regular Article - Theoretical Physics
Seeking evolution of dark energy
Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, 27599-3255, USA
* e-mail: frampton@physics.unc.edu
Received:
2
August
2011
Revised:
10
August
2011
Published online:
2
September
2011
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state ω(Z). We focus on the value of redshift Z
∗ at which the cosmic late time acceleration begins and 
. Four ω(Z) are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era, ∞>Z>−1, such that the future 0>Z>−1 is also sensibly described. If dark energy is represented by a CC model with ω≡−1, the present ranges for Ω
Λ
(t
0) and Ω
m
(t
0) imply that Z
∗=0.743 with 4% error. We discuss the possible implications of a model-independent measurement of Z
∗ with better accuracy.
© Springer-Verlag / Società Italiana di Fisica, 2011
