Cosmological Density Perturbations From A Quantum Gravitational Model Of Inflation

Abstract

We derive the implications for anisotropies in the cosmic microwave background following from a model of inflation in which a bare cosmological constant is gradually screened by an infrared process in quantum gravity. The model predicts that the amplitude of scalar perturbations is $A_S=(2.0\pm .2)\times 10^{-5}$, that the tensor-to-scalar ratio is $r\approx 1.7\times 10^{-3}$, and that the scalar and tensor spectral indices are $n\approx .97$ and $n_T\approx -2.8\times 10^{-4}$, respectively. By comparing the model's power spectrum with the COBE 4-year RMS quadrupole, the mass scale of inflation is determined to be $M=(.72\pm .03)\times 10^{16}\mathrm{GeV}$. At this scale the model produces about $10^8$ e-foldings of inflation, so another prediction is $\Omega =1$.

Comments: 18 pages, LaTeX 2 epsilon, 1 eps file, uses epsfig