How Big Can Entanglement Get? by Andrew Zimmerman Jones.
Our intuition has evolved to deal with the macroscopic world: the world of things you can hold in your hand and see with your naked eyes. But many of the discoveries of the last century, particularly those in quantum physics, have called into question virtually all of those physical intuitions. Even Albert Einstein, whose intuitions were often spot-on, couldn’t bridge the gap between his intuition and the predictions of quantum theory, particularly when it came to the notion of quantum entanglement. Yet we’ve been able to make some peace with quantum mechanics because, for most intents and purposes, its strangest effects are only felt on the micro scale. For everyday interactions with ordinary objects, our intuition still works just fine.
Now, though, physicists are entangling bigger and bigger objects—not just single particles but collections of thousands of atoms. This seemingly-esoteric research could have real technological implications, potentially doubling the accuracy of atomic clocks used in applications such as GPS. But it also challenges the artificial barrier we’ve set up between the microscopic scale, where quantum mechanics rules, and the macroscopic world, where we can count on our intuition. Quantum weirdness is going big.