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Scientists invented a real-life flux capacitor, but not for time travel

By Alma Fabiani

Nov 28, 2020

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Not long ago, I rewatched Back to the Future and while the end credits were scrolling down my TV screen, I couldn’t help but wish that the flux capacitor was a real thing. Being able to travel through time, imagine that! Well, as it turns out, in 2018, scientists from Australia and Switzerland created a real-life flux capacitor. The only problem is that this one doesn’t let you travel back to the 1950s.

The device is actually a new type of electronic circulator that can control the directional movement of microwave signals. The scientists behind this project proposed two different potential circuits, and one of them borrows the same design of the three-pointed flux capacitor Doc Brown and Marty McFly used to travel both to 1955 and 2015. Dreamy, right?

The research, which was published in Physical Review Letters, uses the “quantum tunnelling of magnetic flux around a capacitor, breaking time-reversal symmetry.” Capacitors are common devices in the world of electronics that store energy. The ‘flux’ part of the term flux capacitor, is the amount of something moving across a certain area. In a flux capacitor, microwaves are the ‘something’, and the channel they move across is a central capacitor. In other words, signals circulate around the circuit in only one direction, just like cars on a roundabout.

This makes the device perfect for quantum computing, where researchers need to direct signals with precision—not the kind of time travelling you had in mind, unfortunately. The fact that this device forces microwaves to flow in only one direction around a central area makes it remarkable because it breaks something called time-reversal symmetry—a theoretical law of physics that states that if you reversed time, you’d see whatever just happened, happen exactly in reverse.

So, what’s the point, you ask? Not only can this technology pave the way for quantum computing but it can also lead to better radar as well as improved WiFi and mobile antennas (think 5G and everything that goes with it). Granted, this doesn’t sound quite as exciting as time travel.