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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