Energy Efficiency Breakthrough Defies 156-Year-Old Law of Physics

Researchers have questioned long-held magnetic coupling beliefs to create the first ever device that behaves like a diode for magnetic fields. The work could forever change how we charge batteries.
Loukia Papadopoulos

Researchers at the University of Sussex have made a breakthrough that could forever change how we charge our phone, laptop and even car batteries. The unique work has revealed, for the first time ever, that coupling between two magnetic elements can be made asymmetrical, defying a 156-year-old law of physics. 

A diode for magnetic fields

“We have created the first device that behaves like a diode for magnetic fields," explained Jordi Prat-Camps. The novel research demonstrates that it is possible to make magnets connect to each other without the connection happening in the opposite direction.


This theory goes against magnetic coupling beliefs that have been undisputed since the 19th century where they first emerged from four Maxwell equations derived from the seminal works of Michael Faraday and James Clerk Maxwell. The equations today describe all electromagnetic phenomena.

“The magnetic coupling between magnets or circuits is something extremely well-known," explained Prat-Camps. "A vast majority of the technologies we rely on today are based on magnetic coupling including motors, transformers, low-frequency antennas and wireless power transfer devices."

The first to consider breaking magnetic reciprocity

However, the researcher believes his team is the first to ever ponder whether these rules could be tampered with. "As far as we know, nobody before us thought to ask whether this symmetry could be broken and to what extent," said Prat-Camps.

Researchers working with other kinds of metamaterials were already exploring the possibility of breaking reciprocity for light and sound waves. So, Prat-Camps decided to explore the same possibility in magnetic fields.

The first several efforts were unsuccessful until the team conceived of using an electrical conductor in movement. They proceeded to solve Maxwell’s equations analytically in order to demonstrate that not only could reciprocity be broken but that coupling could also be made maximally asymmetric.

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The team found that the coupling from A to B would be different from zero but from B to A it would be exactly zero. Once the potential of unidirectional coupling was proven theoretically, the researchers then engineered a proof-of-concept experiment which confirmed their findings.

Improving recharging efficiencies

Now, Prat-Camps believes his breakthrough may open the doors to advancements that could forever change the ability of wireless power transfer technologies to improve the recharging efficiency of everything from phones to cars.

"Electric diodes are so crucial that none of the existing electronic technologies such as microchips, computers or mobile phones would be possible without them. If our result for magnetic fields would have one millionth of the same impact as the developments in electric diodes, it would be a hugely impactful success," explained the researcher.

For years, Prat-Camps’ work has focused on the manipulation of magnetic fields via the use of metamaterials. Recent endeavors have seen his team develop new tools to control magnetism that seem straight out of a science fiction novel. Amongst their other inventions are included magnetic undetectability cloaks, magnetic concentrators, and even wormholes. Yes, wormholes!

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