For A Split Second, A (Simulated) Particle Went Backward In Time
The uncertainty principle, which lies at the heart of quantum mechanics, states that, at any given moment, either the location or the velocity of a subatomic particle can be specified, but not both. “Because of the uncertainty principle, the quantum ball will never return back to the point of the origin,” Dr. Vinokur said. Moreover, in quantum mechanics, the ball is actually a wave: Once its location is known, it spreads like ripples on a pond and evolves.
Source: www.nytimes.com