  The purpose of this work is to use active particles to study the effect of
facilitation on supercooled liquids. To this end we investigate the behavior of
a model supercooled liquid doped with intermittently active and intermittently
slowed particles. To simulate a facilitation mechanism, the active particles
are submitted intermittently to a force following the mobility of the most
mobile molecule around, while the slowed particles are submitted to a friction
force. We observe upon activation, a fluidization of the whole medium
simultaneously to a large increase of the dynamic heterogeneity. This effect is
reminiscent of the fluidization observed with molecular motors doping of the
medium. When the mobility characteristic time used in the facilitation
mechanism matches the physical time characterizing the spontaneous mobility
aggregation of the material, we observe a phase transition associated with a
structural aggregation of active molecules. This transition is accompanied by a
sharp increase of the fluidization and dynamic heterogeneity.
