Magnetic field invisibility discovered by Barcelona-based researchers, a first step towards the invisibility of light

Barcelona (ACN).- Imagine a metal object through which magnetic fields can go without any visible alteration, and thus without being detected. Researchers from the Universitat Autònoma de Barcelona (UAB, Barcelona’s Autonomous University) have developed a metal cylinder that is invisible to magnetic fields. Furthermore, any object placed inside also becomes invisible. This research, carried out with the collaboration of a team from the Science Academy of Slovakia, was published on Saturday in the prestigious journal ‘Science’. No one had ever achieved such results in such a simple manner, with much precision in the theoretical calculations and conclusive results in the laboratory. They believe this discovery is the first step towards reaching light’s invisibility, a goal on so many occasions characterised in science-fiction books, but a goal that now seems much more achievable. “Until 10 years ago, invisibility was a science-fiction idea, but in the last decade it has started to become part of science, and our research is a step in the right direction to achieving it”, stated the Physics Professor at the UAB who headed the study, Àlvar Sánchez. Besides the high value significance of this study from a theoretical base, the discovery can also have many practical implementations. For instance heart pacemakers could be built based on this new knowledge so they are not affected by magnetic fields, such as in airport metal detectors.

Magnetic fields are absolutely essential for the production of electric power, since 99% of the energy consumed is generated thanks to these magnetic fields inside power plant turbines. Furthermore, they are essential for the design of any type of mechanical engines, as well as in computer memories or in mobile telephones. Therefore, knowing how to better control magnetic fields is an important scientific milestone for technological development. How to eliminate magnetic fields in given spaces was a scientific and technological challenge. The UAB study opens up this possibility.

How does it go?

The cylinder has been developed with superconductors and iron-magnetic materials, which can easily be found on the market. The formula to build an invisible object for magnetic fields is quite simple and easy to understand. The cylinder has two parts, an external part made out of an alloy of iron, nickel and chrome and an internal part made out of a superconductor material put at high temperature that can be easily cooled down using liquid nitrogen. The superconduction layer of the cylinder’s inside avoids the magnetic field to reach the void space. Furthermore it distorts the external field and makes the cylinder detectable. To avoid this, the iron-magnet external layer, made out of an alloy of iron, nickel and chrome, produces the opposite effect. It attracts the magnetic field line and exactly compensates the distortion created by the superconductor, but without the magnetic field reaching the cylinder’s inside. The effect is a magnetic field absolutely null in the inside and without absolutely any distortions in the external magnetic field.

The original equation was found in Catalonia

The Catalan researchers are headed by Professor Àlvar Sánchez, from the Electromagnetic Unit of UAB Physics Department. They found the mathematical formula to design the device: a cylinder described by an extraordinarily simple equation that would theoretically allow the device to be absolutely undetectable by magnetic fields. Furthermore, this cylinder would make any object put inside undetectable. With this equation, UAB scientists contacted a lab specialised in the precise measurement of magnetic fields to build the device. It was the Electric Engineering Institute of the Science Academy of Slovakia, in Bratislava.

In only some months, the experimental results have been absolutely convincing. The cylinder is completely invisible to magnetic fields, it turns any object put inside invisible and completely isolates this object from external fields.

The research study, published in ‘Science’ on Saturday March 24^th, was developed by the UAB’s Àlvar Sánchez, Carles Navau and Jordi Prat. The Slovak team was Fedor Gömöry, Mykola Solovyov and Ján Souc.