From de Sitter to de Sitter: Decaying Vacuum Models as a Possible Solution to the Main Cosmological Problems

Figure 2

Solution of the coincidence problem in running vacuum cosmologies. The right graphic is our model; the left is CDM. Solid and dashed lines represent the evolution of the vacuum () and total matter-radiation () density parameters for n=2, , and . The late time coincidence between the density parameter of the vacuum and material medium (left circle) has already occurred at very early times (right circle). Note also that the values 5 and 75 in the horizontal axis were glued in order to show the complete evolution (the suppressed part presents exactly the same behavior). Different values of change slightly the value of the redshift for which at the very early Universe (see also discussion in the text).