Not sure what "actual physical phenomenon" means, but probably no. If you mean can you look at a photon and observe something about it that tells you it's enta

Not sure what "actual physical phenomenon" means, but probably no. If you mean can you look at a photon and observe something about it that tells you it's entangled to some other photon, no. If you mean do we know what physical process underlies entanglement, also no. If you mean does entanglement really happen as opposed to being theoretical, yes. The link from the first paragraph of the article may help: https://www.scientificamerican.com/article/chinese-researchers-achieve-stunning-quantum-entanglement-record/ https://www.scientificamerican.com/article/chinese-researche...