Slides of 5 lectures at XV Brazilian School on Cosmology and ...

Dressed cosmological parametersH is gre<strong>at</strong>er than wall Hubble r<strong>at</strong>e; smaller than voidHubble r<strong>at</strong>e measured by wall (or any one set <strong>of</strong>) clocks¯H(t) = 1 ādādt = 1 a vda vdτ v= 1 a wda wdτ w< H < 1 a vda vdτ wFor tracker solution H = (4f v 2 + f v + 4)/6tDressed average deceler<strong>at</strong>ion parameterq = −1H 2 a 2 d 2 adτ 2 wCan have q < 0 even though ¯q = −1¯H 2 ā 2 d 2 ādt 2 > 0; difference<strong>of</strong> clocks important.15th <strong>Brazilian</strong> <strong>School</strong> on Cosmology and Gravit<strong>at</strong>ion, August 2012 – p.65/143