Predictions of quantum gravity in inflationary cosmology: effects of the Weyl-squared term. (arXiv:2005.10293v1 [hep-th])

Predictions of quantum gravity in inflationary cosmology: effects of the Weyl-squared term. (arXiv:2005.10293v1 [hep-th])
<a href="http://arxiv.org/find/hep-th/1/au:+Anselmi_D/0/1/0/all/0/1">Damiano Anselmi</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Bianchi_E/0/1/0/all/0/1">Eugenio Bianchi</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Piva_M/0/1/0/all/0/1">Marco Piva</a>

We derive the predictions of quantum gravity with fakeons on the amplitudes
and spectral indices of the scalar and tensor fluctuations in inflationary
cosmology. The action is $R+R^{2}$ plus the Weyl-squared term. The ghost is
eliminated by turning it into a fakeon, that is to say a purely virtual
particle. We work to the next-to-leading order of the expansion around the de
Sitter background. The consistency of the approach puts a lower bound ($
m_{chi }>m_{phi }/4$) on the mass $m_{chi }$ of the fakeon with respect to
the mass $m_{phi }$ of the inflaton. The tensor-to-scalar ratio $r$ is
predicted within less than an order of magnitude ($4/3<N^{2}r<12$ to the
leading order in the number of $e$-foldings $N$). Moreover, the relation
$rsimeq -8n_{T}$ is not affected by the Weyl-squared term. No vector and no
other scalar/tensor degree of freedom is present.

We derive the predictions of quantum gravity with fakeons on the amplitudes
and spectral indices of the scalar and tensor fluctuations in inflationary
cosmology. The action is $R+R^{2}$ plus the Weyl-squared term. The ghost is
eliminated by turning it into a fakeon, that is to say a purely virtual
particle. We work to the next-to-leading order of the expansion around the de
Sitter background. The consistency of the approach puts a lower bound ($
m_{chi }>m_{phi }/4$) on the mass $m_{chi }$ of the fakeon with respect to
the mass $m_{phi }$ of the inflaton. The tensor-to-scalar ratio $r$ is
predicted within less than an order of magnitude ($4/3<N^{2}r<12$ to the
leading order in the number of $e$-foldings $N$). Moreover, the relation
$rsimeq -8n_{T}$ is not affected by the Weyl-squared term. No vector and no
other scalar/tensor degree of freedom is present.

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