… or perhaps not.
Entanglement Is Not That Magic
That said, though, it’s fairly common to hear claims of the form “when two particles are entangled, anything you do to one of them changes the state of the other.” This is not strictly true, though, and it’s worth going through in detail, if only so I have something to point to the next time somebody starts using that line. This will necessarily involve some math, but I’ll try to keep it as simple as I can.