Advanced Physics

2. Take the flat-space ACDM model, with Hubble parameter at the present H = 70 km s Mpc and density parameters , = 0.70 and mo = 0.30. (Disregard the contributions from radiation at the present time (, .) Let's hypothesize that what might have happened after inflation in the early universe, happens again in the far future. (a) Determine the value of the Hubble parameter at a time t > to. (b) Assume that the vacuum energy of the cosmological constant decays suddenly into radiation at time t = 50t . Determine the energy density of the photons right after the decay. (c) What will be the energy density of matter at t = 50t, ? (d) A long time after the vacuum energy decays at t = 50t, matter will again start dominating the expansion. Find this time