Quintessence in a quandary: Prior dependence in dark energy models
Physical Review D
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 parametrisation, 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
... on gain for a given survey and show that, because of the non-trivial 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.