Dude?

In physics, systems traveling forward in time evolve from a simple state to a more complicated one—known as the thermodynamic arrow of time. For example, if you were to put a drop of ink into a glass of water, initially it would have a well-defined state. However, it soon starts to spread out and within a few minutes it will have uniformly dissolved into the water. If time were reversed for a human, they would become younger.

In a study published in the journal Scientific Reports, scientists from the U.S. and Russia have experimentally demonstrated time reversal—sending a qubit from a more complicated state to a simpler one.

The algorithm they suggest changes the quantum developed state so it starts to develop back in time. “Doing this magic with the developed state of ink we will see that after the same time (time needed for the dissolving of ink in the water) the ink will again combine back into the original drop,” study author Andrei Lebedev told Newsweek. “This is exactly what we did in our work where the drop of ink is state of three qubits, and the water is a Hilbert state of the quantum computer.”