The familiar laws of physics don’t map intuitively to the subatomic world, which is made up of quantum particles called qubits that can technically exist in more than one state simultaneously—a phenomenon known as quantum entanglement.
Now, in a new study carried out by the Spaniards Miguel Navascués and David Trillo, from the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (ÖAW), and the experimental physics group of the University of Vienna of which the Austrian Philip Walther is a part, reports how to advance and rewind the clocks of these quantum particles.
“In a cinema (classical physics) a film is projected from beginning to end, regardless of what the public wants,” said Navascués. “But at home (quantum physics), we have a remote control to manipulate the film. We can go back to a previous scene or skip several scenes forward. We’ve made science fiction real!”
By developing a “rewind protocol,” the team was able to revert an electron to a previous state — something that would have worked for any other particle, like a proton or muon, for example. In experiments, they say, they were able to demonstrate the use of a “quantum switch” to revert a photon to its original state before going through glass.
While it’s an exciting prospect, expanding the technique could prove extremely difficult, if not impossible.
“If we could lock a person in a box with zero outside influences, it would be theoretically possible,” Navascués noted. “But with our currently available protocols, the chance of success would be very, very low.”
And there is also an even bigger hurdle.
“In addition, the time required to complete the process depends on the amount of information that the system can store,” added the Spanish researcher. “A human being is a physical system that contains an enormous amount of information. It would take millions of years to rejuvenate a person by less than a second, so it doesn’t make sense.”
Furthermore, the system is only capable of reversing the state of a certain particle. However, to speed up time, the researchers have an ace up their sleeve.
‘We found that evolutionary time can be transferred between identical physical systems,’ they explained. “In a one-year experiment with ten systems, you can steal one year from each of the first nine systems and give them all to the tenth.”
So instead of recreating Back to the Future and exclaiming “Holy science!” Like the Doc, the authors see more mundane practical applications of their discovery. For example, the qubit states of a quantum processor could be reversed, allowing researchers to undo mistakes during its development.