Degeneracy inherent in the observational determination of the dark energy equation of state
Abstract
Using a specific model for the expansion rate of the Universe as a function of scale factor, it is demonstrated that the equation of state of the dark energy cannot be determined uniquely from observations at redshifts z≲a few unless the fraction of the mass density of the Universe in nonrelativistic particles, Ω_{M}, somehow can be found independently. A phenomenological model is employed to discuss the utility of additional constraints from the formation of large scale structure and the positions of cosmic microwave background peaks in breaking the degeneracy among models for the dark energy.
 Publication:

Physical Review D
 Pub Date:
 December 2002
 DOI:
 10.1103/PhysRevD.66.123511
 arXiv:
 arXiv:astroph/0203137
 Bibcode:
 2002PhRvD..66l3511W
 Keywords:

 98.80.k;
 98.80.Es;
 Cosmology;
 Observational cosmology;
 Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 12 pages, 3 figures. Several references added