Quintessence in a quandary: Prior dependence in dark energy models
Abstract
The archetypal theory of dark energy is quintessence: a minimally coupled scalar field with a canonical kinetic energy and potential. By studying random potentials, we show that quintessence imposes a restricted set of priors on the equation of state of dark energy. Focusing on the commonly used parametrization, w (a )≈w_{0}+w_{a}(1 a ) , we show that there is a natural scale and direction in the (w_{0},w_{a}) plane that distinguishes quintessence as a general framework. We calculate the expected information gain for a given survey and show that, because of the nontrivial prior information, it is a function of more than just the figure of merit. This allows us to make a quantitative case for novel survey strategies. We show that the scale of the prior sets target observational requirements for gaining significant information. This corresponds to a figure of merit FOM ≳200 , a requirement that future galaxy redshift surveys will meet.
 Publication:

Physical Review D
 Pub Date:
 November 2014
 DOI:
 10.1103/PhysRevD.90.105023
 arXiv:
 arXiv:1406.2301
 Bibcode:
 2014PhRvD..90j5023M
 Keywords:

 11.10.z;
 02.50.Ng;
 95.36.+x;
 98.80.k;
 Field theory;
 Distribution theory and Monte Carlo studies;
 Dark energy;
 Cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 5 pages, 3 figures. For the busy reader, Fig. 1 is the money plot. v2: Minor changes, matches published version. Code open source at gitorious.org/randomquintessence