Real-life flux capacitor inspired by Back to the Future

Fans of the Back to the Future movie trilogy will be well aware that Dr Emmett Brown’s time-travelling DeLorean is powered by what he dubs a ‘flux capacitor’. Now, Australian and Swiss physicists have invented their own version of the device, and while it might not run a time machine, they say it will have important applications in communication technology and quantum computing.

The team from The University of Queensland (UQ), RMIT University and ETH Zurich have proposed a device which uses the quantum tunnelling of magnetic flux around a capacitor which they say can break time-reversal symmetry. Published in the journal Physical Review Letters, their research proposes a new generation of electronic circulators — devices that control the direction in which microwave signals move.

RMIT Professor Jared Cole said the device would be built from a superconductor, in which electricity could flow without electrical resistance. “We propose two different possible circuits, one of which resembles the iconic three-pointed-star design of the cinematic flux capacitor,” he said.

“In it, quantum ‘tubes’ of magnetic flux move around a central capacitor by a process known as quantum tunnelling, where they overcome classically insurmountable obstacles.”

An illustration of the researchers’ proposed circuit, resembling the iconic flux capacitor as seen on-screen.

The combination of magnetic fields and electric charges leads to what the physicists call broken time-reversal symmetry, though sadly the effect does not allow them to travel back in time.

“Instead, it makes radio signals circulate around the circuit in only one direction, much like cars on a roundabout,” said UQ Professor Tom Stace.

“Such a device could be used to isolate parts of an experimental apparatus from each other, which is crucial when the individual parts are extremely sensitive quantum systems.”

ETH Zurich’s Dr Clemens Mueller said the device is a crucial component for next-generation technologies, including the long sought-after quantum computer. He noted, “Our research makes an important step towards scaling up this technology, where researchers need to precisely direct control and measurement signals around a quantum computer.”

The research could also find application in developing better electronics for mobile phone and Wi-Fi antennas, as well as improving radar.

Top image credit: ©stock.adobe.com/au/Cybrain