Time Reversal: Scientists Achieves A Real-Life Sci-Fi Breakthrough

Austrian scientists have pulled off something that sounds straight out of science fiction: they’ve successfully reversed time for a single photon using a device called a quantum switch. This isn’t about building a time machine to visit the dinosaurs—it’s about manipulating the flow of time within quantum systems, where the rules of reality bend in mind-boggling ways.

What They Did

• Researchers from the Austrian Academy of Sciences (ÖAW) and the University of Vienna used a photon (a particle of light) and sent it through a crystal.
• With the help of the quantum switch, they were able to rewind the photon’s state—returning it to how it was before the journey began.
• This process, called a rewind protocol, works even without knowing what happened to the particle during its journey—a feat previously thought impossible in quantum mechanics.

Image Credits – S. Kelley/JQI

Fast-Forwarding Time Too

• The team didn’t stop at rewinding. They also discovered how to accelerate time for a quantum system.
• By redistributing “evolutionary time” among identical systems, they made one system age 10 years in just one, while the others remained unchanged.

Why It Matters

• While reversing time for humans is far beyond reach (it would take millions of years to rewind even one second of a person’s life), this discovery could revolutionize quantum computing.
• It opens the door to undoing errors in quantum processors, making them more powerful and reliable.

A New Way to Watch Reality

Physicist Miguel Navascués likened classical physics to watching a movie in a theater—linear and unchangeable. Quantum physics, he said, is like watching at home with a remote: you can rewind, fast-forward, or skip scenes.