Hitting the ‘Rewind’ Button & Travelling Through Time is Possible, Study Hints
© Photo : Azmat Ullah - Creative Commons
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The possibility of time travel – the concept of movement between certain points in time – has long captivated the minds of both scientists and science fiction writers alike. Scientific theories about time travel abound, interspersed with terms like wormholes, black holes, and space-time warp.
"We have made science fiction come true," a collaboration of scientists has announced, claiming they have discovered a trick to speed up time.
"It’s possible to "accelerate, decelerate and reverse the flow of time within arbitrary, even uncontrolled quantum systems," Spanish researchers Miguel Navascués and David Trillo, from the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (ÖAW), along with Austrian researcher Philip Walther, and the University of Vienna’s experimental physics group have discovered.
The scientists have revealed in a spate of papers published on preprint servers that quantum particles – the smallest physical particle that can exist without being broken down – can be rejuvenated or reverted to a previous state.
“In a theater, [classical physics], a movie is projected from beginning to end, regardless of what the audience wants. But at home [the quantum world], we have a remote control to manipulate the movie. We can rewind to a previous scene or skip several scenes ahead,” was the analogy that Miguel Navascués used to explain the finding.
Developed by scientists from the Austrian Academy of Sciences, a “rewind protocol” enables any particle, such as an electron or proton, to revert to different quantum states from different points in time. David Trillo proved this, both in theory and experimentally, by using a photon that evolves while passing through a crystal. A “quantum switch” experimental device was used to allow a photon of light to revert to its previous state.
“It was one of the most difficult experiments we’ve ever built for a single photon. The fascinating thing is that [the particles] can return to a state you know nothing about," Philip Walther told Spanish media.
21 February 2020, 14:22 GMT
"We present a universal mechanism that, when it acts on any qubit, propagates it to the state it was in before the experiment began... We answered the question of whether such processes are allowed by the laws of quantum mechanics,” the scientists said.
They pointed out that unlike earlier discovered protocols that offered a certain "probability level," the new mechanism can be relied upon to always prove successful, unless the experimental device is totally “invisible” to the qubit – the basic unit of quantum information in quantum computing.
As to whether one could replicate this experiment with a human, the team explained it would be practically impossible.
"If we could lock a person in a box with zero external influences, it would be theoretically possible. But with our currently available protocols, the probability of success would be very, very low. Also, the time needed to complete the process depends on the amount of information the system can store. A human being is a physical system that contains an enormous amount of information. It would take millions of years to rejuvenate a person for less than a second, so it doesn’t make sense.”
The finding isn't a time machine, the scientists emphasized.
“If you want to revert a particle capable of storing one bit of information to its state five minutes ago, that’s the amount of time needed to complete the process,” said Miguel Navascués.
This finding, according to one of the researchers, Philip Walther, has practical implications, as he said that it could have "technological applications," such as a "rewind protocol in quantum processors used to reverse unwanted errors or developments.”
