CALIFORNIA - An ‘angel particle’ which is both matter and anti-matter has been discovered 80 years after its existence was first proposed by physicists. Researchers revealed that they have found the first evidence of the elusive particles in what is being described as a ‘landmark’ moment in quantum physics.

The discovery could help scientists to bring a quantum computing revolution, which would allow us to make machines many times more powerful than those made using existing technology. Scientists have theorised that when the Big Bang first created the universe, equal amounts of matter and anti-matter were produced.

Anti-matter is made from particles which are the ‘anti-particles’ of those from normal matter.

Researchers also predicted that if the two kinds of matter would ever meet, they would destroy each other, leaving only a burst of energy behind. But in 1937, an Italian physicist called Ettore Majorana suggested that another class of particles could exist - which were their own anti-particles.

He called these particles ‘fermions’.

Now researchers have found the first evidence that these particles could exist.

The scientists named their discovery the ‘Angel Particle’ after the novel Angels and Demons by Dan Brown, which includes the making of a bomb from the combination of matter and anti-matter.

Professor Shoucheng Zhang, a Standford University physicist, said: ‘Our team predicted exactly where to find the Majorana fermion and what to look for as its ‘smoking gun’ experimental signature.

‘This discovery concludes one of the most intensive searches in fundamental physics, which spanned exactly 80 years.’

To find proof that fermions exist, the scientists first needed to find ‘quasi-particles’.

Quasi-particles are particle-like excitations that arise out of the behaviour of superconducting materials. 

While quasiparticles are not like particles found in nature, they fit the mathematical requirements to be considered real Majorana fermions.

In the experiments, the team stacked thin films of two quantum materials – a superconductor and a magnetic topological insulator – and sent an electrical current through them, all inside a chilled vacuum chamber.

The top film was a superconductor. The bottom one was a topological insulator, which conducts current only along its surface or edges but not through its middle.

Putting them together created a superconducting topological insulator, where electrons zip along two edges of the material’s surface without resistance, like cars on a superhighway.

The researchers then added a small amount of magnetic material to the insulator, which made the electrons flow one way along one edge of the surface and the opposite way along the opposite edge.

Then the researchers swept a magnet over the stack. This made the flow of electrons slow, stop and switch direction.

These changes were not smooth, but took place in abrupt steps, like identical stairs in a staircase.

At certain points in this cycle, quasiparticles emerged, arising in pairs out of the superconducting layer and travelling along the edges of the topological insulator just as the electrons did.

If fermions exist, they could help scientists to build quantum computers, which would allow us to build all-power and super-fast machines, it has been suggested.

Quantum computers are yet to be developed on a large scale because they need to be well-insulated from environmental noise.

Researchers have suggested that a single quantum bit of information could theoretically be stored in two separate fermions.

This would mean that if one fermion was damaged by environmental noise, the other would remain intact.

Researchers said the new discovery could lead to a ‘breakthrough’ for quantum processing.

‘It does seem to be a really clean observation of something new,’ said Professor Frank Wilczek, a theoretical physicist and Nobel laureate at the Massachusetts Institute of Technology.

‘It’s not fundamentally surprising, because physicists have thought for a long time that Majorana fermions could arise out of the types of materials used in this experiment.

‘But they put together several elements that had never been put together before, and engineering things so this new kind of quantum particle can be observed in a clean, robust way is a real milestone.’

And Professor Tom Devereaux, from Stanford University, said: ‘This research culminates a chase for many years to find chiral Majorana fermions. It will be a landmark in the field.’

DM