Beautiful new experiment verifies (yet again) that quantum mechanics is weird

A new experiment carried out in the Netherlands has confirmed the “spooky action at a distance” that is a central feature of quantum mechanics.  There have been several such confirmations, going back to the early 1980s, but this is is the first one that simultaneously closes all the loopholes that might arise.  It may therefore be the final blow to the idea — championed by Einstein and Bell, among others — that quantum mechanics is incomplete and there might be local “hidden variables.”

The preprint version of the paper is available here.