New report out of Delft University has shown the successful demonstration of quantum entanglement of two strips of silicon resonators, consisting of roughly 10 billion atoms!
They demonstrated quantum entanglement and violations of Bell’s inequality—a canonical test of the principle that all influences on a particle are local and that particle states exist independently of the observer. They used two mechanical resonators, each containing roughly 10 billion atoms.
If you do not have access to the PRL paper, you may read the arXiv version here.
This is quite a feat, and I think that things can only get bigger, literally and figuratively.