  Phonons, the quanta of vibrations, are very important for the equilibrium and
dynamical properties of matter. GHz coherent phonons can also interact with and
act as interconnects in a wide range of quantum systems. Harnessing and
tailoring their coupling to opto-electronic excitations thus becomes highly
relevant for engineered materials for quantum technologies. With this
perspective we introduce polaromechanical metamaterials, two-dimensional arrays
of $\mu$m-size zero-dimensional traps confining light-matter polariton fluids
and GHz phonons. A strong exciton-mediated polariton-phonon interaction
determines the inter-site polariton coupling with remarkable consequences for
the dynamics. When locally perturbed by optical excitation, polaritons respond
by locking the energy detuning between neighbor sites at integer multiples of
the phonon energy, evidencing synchronization involving the polariton and
phonon fields. These results open the path for the coherent control of quantum
light fluids with hypersound in a scalable platform.
