http://arxiv.org/abs/2212.13561
We construct an asymmetric bouncing scenario within the VCDM model, a modified gravity theory with two local physical degrees of freedom. The scenario is exempt of any ghost or gradient instability, and avoids any singularity problem, ad-hoc matching conditions or anisotropic stress issue (BKL instability). It moreover succeeds in generating the cosmological perturbations compatible with the observations. The scalar spectral index can be adapted by the choice of the equation of state of the matter sector and the form of the VCDM potential leading to an almost scale-invariant power spectrum. Satisfying the CMB bounds on the tensor-to-scalar ratio leads to a blue tensor spectrum.
A. Ganz, P. Martens, S. Mukohyama, et. al.
Thu, 29 Dec 22
39/47
Comments: 14 pages, 8 figures