According to quantum theory, that paradoxical body of rules governing the subatomic universe, not even a single particle can reverse its own course through time. The wave function extends throughout space and time. But getting a wave function to go in reverse is no small trick. But if it’s a quantum ball, the uncertainty principle kicks in: You can know how hard to hit the ball, or in which direction to hit it, but not both. “Because of the uncertainty principle, the quantum ball will never return back to the point of the origin,” Dr. Vinokur said.

Source: New York Times May 08, 2019 13:10 UTC