  Cells not only can have self-motility by crawling, but also are capable of
other types of active motions like periodic contraction or pulsation. In this
work, by using the Voronoi cell model, we show how this non-motility activity
affects the structure, dynamic and density fluctuations of cellular monolayers.
We found that random cell pulsation can fluidize solid epithelial tissues,
resulting in a \emph{hyperuniform} fluid state, while pulsation synchronization
inhibits the fluidity, causes a reversed solidification. We prove this
solidification is BKT-type transition, characterized by strong density/dynamic
heterogeneity arising from the creation of topological defects in the pulsating
phase space. The magnitude and length scale of density heterogeneity diverge as
the pulsating period increases, resulting in an opposite \emph{giant} density
fluctuation. Our findings accord with recent experimental observations and can
be quantitatively explained by a proposed fluctuating hydrodynamic theory.
