Uncertain Principles: Entanglement Happens

(Oops. I accidentally hit publish instead of save yesterday, and didn’t add my comment. Hence the time travel on the post.)

There are several application people try and use entanglement to pull off some neat trick (e.g. clock synchronization) and the problems Chad points out are often glossed over. It’s almost like the famous Sidney Harris cartoon, “Then a miracle occurs,” when the step in the procedure is “we take our entangled particles and move them an arbitrary distance apart,” which ignores the little demons Chad describes, that compromise your ability to know the measurement basis after your system has been exposed to the real world. It’s not quite at the level of ignoring the second law of thermodynamics and proposing a perpetual motion machine, but it’s almost as naive to propose it for an arbitrary system, without working out the details.