Multiple transitions in vacuum dark energy and $H_0$ tension

Understand

We study the effects of multiple transitions in the vacuum dark energy density on the $H_0$ tension problem.

• We consider a phenomenological model in which the vacuum energy density undergoes multiple transitions in the early as well as the late universe and compare the model's predictions using the three sets of data from CMB+BAO+SN.
• The transient dark energy can be either positive (dS-like) or negative (AdS-like).
• We conclude that a transient late-time AdS-type vacuum energy typically yields the higher value of $H_0$ which can alleviate the $H_0$ tension.