Intrinsic uncertainty on the nature of dark energy

Wessel Valkenburg, Martin Kunz, Valerio Marra
2013 Physics of the Dark Universe  
We argue that there is an intrinsic noise on measurements of the equation of state parameter w=p/ρ from large-scale structure around us. The presence of the large-scale structure leads to an ambiguity in the definition of the background universe and thus there is a maximal precision with which we can determine the equation of state of dark energy. To study the uncertainty due to local structure, we model density perturbations stemming from a standard inflationary power spectrum by means of the
more » ... xact Lemaître-Tolman-Bondi solution of Einstein's equation, and show that the usual distribution of matter inhomogeneities in a ΛCDM cosmology causes a variation of w -- as inferred from distance measures -- of several percent. As we observe only one universe, or equivalently because of the cosmic variance, this uncertainty is systematic in nature.
doi:10.1016/j.dark.2014.01.001 fatcat:7uuqqv4fszh5tnv5zhcthnvlny