Cosmology with relativistically varying physical constants
  We have shown that the varying physical constant model is consistent with the
recently published variational approach wherein Einstein equations are modified
to include the variation of the speed of light c, gravitational constant G and
cosmological constant {\Lambda} using the Einstein-Hilbert action. The general
constraint resulting from satisfying the local conservation laws and contracted
Bianchi identities provides the freedom to choose the form of the variation of
the constants as well as how their variations are related. When we choose
dG/Gdt=3dc/cdt, c=c_0.exp[(a^{\alpha}-1)], G=G_0.exp[3(a^{\alpha}-1)] and
{\Lambda}={\Lambda}_0.exp[(a^(-{\alpha})-1)], where a is the scale factor and
{\alpha}=1.8, we are able to show that the resulting model: (a) fits the
supernovae 1a observational data marginally better than the {\Lambda}CDM model;
(b) determines the first peak in the power spectrum of the cosmic microwave
background temperature anisotropies at multipole value of l=217.3; (c)
calculates the age of the universe as 14.1 Gyr; and (d) finds the BAO acoustic
scale to be 145.2 Mpc. These numbers are within less than 3% of the values
derived using the {\Lambda}CDM model. Surprisingly we find that the dark-energy
density is negative in a universe that has significant negative curvature and
whose expansion is accelerating at a faster rate than predicted by the
{\Lambda}CDM model.
