Cosmology with decaying cosmological constant -- exact solutions and model testing

Understand

We study dynamics of $\Lambda(t)$ cosmological models which are a natural generalization of the standard cosmological model (the $\Lambda$CDM model).

• We consider a class of models: the ones with a prescribed form of $\Lambda(t)=\Lambda_{\text{bare}}+\frac{\alpha^2}{t^2}$.
• This type of a $\Lambda(t)$ parametrization is motivated by different cosmological approaches.
• We interpret the model with running Lambda ($\Lambda(t)$) as a special model of an interacting cosmology with the interaction term $-d\Lambda(t)/dt$ in which energy transfer is between dark matter and dark energy sectors.