Cosmological Constraints on $Lambda$(t)CDM Models
H. A. P. Macedo, L. S. Brito, J. F. Jesus, M. E. S. Alves
arXiv:2305.18591v4 Announce Type: replace
Abstract: Problems with the concordance cosmology $Lambda$CDM as the cosmological constant problem, coincidence problems and Hubble tension has led to many proposed alternatives, as the $Lambda(t)$CDM, where the now called $Lambda$ cosmological term is allowed to vary due to an interaction with pressureless matter. Here, we analyze one class of these proposals, namely, $Lambda=alpha’a^{-2}+beta H^2+lambda_*$, based on dimensional arguments. Using SNe Ia, cosmic chronometers data plus constraints on $H_0$ from SH0ES and Planck satellite, we constrain the free parameters of this class of models. By using the Planck prior over $H_0$, we conclude that the $lambda_*$ term can not be discarded by this analysis, thereby disfavouring models only with the time-variable terms. The SH0ES prior over $H_0$ has an weak evidence in this direction. The subclasses of models with $alpha’=0$ and with $beta=0$ can not be discarded by this analysis. Finally, by using distance priors from CMB, the $Lambda$ time-dependence was quite restricted.arXiv:2305.18591v4 Announce Type: replace
Abstract: Problems with the concordance cosmology $Lambda$CDM as the cosmological constant problem, coincidence problems and Hubble tension has led to many proposed alternatives, as the $Lambda(t)$CDM, where the now called $Lambda$ cosmological term is allowed to vary due to an interaction with pressureless matter. Here, we analyze one class of these proposals, namely, $Lambda=alpha’a^{-2}+beta H^2+lambda_*$, based on dimensional arguments. Using SNe Ia, cosmic chronometers data plus constraints on $H_0$ from SH0ES and Planck satellite, we constrain the free parameters of this class of models. By using the Planck prior over $H_0$, we conclude that the $lambda_*$ term can not be discarded by this analysis, thereby disfavouring models only with the time-variable terms. The SH0ES prior over $H_0$ has an weak evidence in this direction. The subclasses of models with $alpha’=0$ and with $beta=0$ can not be discarded by this analysis. Finally, by using distance priors from CMB, the $Lambda$ time-dependence was quite restricted.