Elusive particle that is its own antiparticle observed

Scientists have observed an exotic particle that behaves simultaneously like matter and antimatter, an advance that could yield powerful computers based on quantum mechanics.
Using a two-storey-tall microscope floating in an ultralow-vibration lab at Princeton University's Jadwin Hall, the scientists captured a glowing image of a particle known as a "Majorana fermion" perched at the end of an atomically thin wire - just where it had been predicted to be after decades of study and calculation dating back to the 1930s.
"This is the most direct way of looking for the Majorana fermion as it is expected to emerge at the edge of certain materials," said Ali Yazdani, a professor of physics who led the research team.

The hunt for the Majorana fermion began in the earliest days of quantum theory when physicists first realised that their equations implied the existence of "antimatter" counterparts to commonly known particles such as electrons.
In 1937, Italian physicist Ettore Majorana predicted that a single, stable particle could be both matter and antimatter. Although many forms of antimatter have since been observed, the Majorana combination remained elusive.
Despite combining qualities usually thought to annihilate each other - matter and antimatter - the Majorana fermion is surprisingly stable; rather than being destructive, the conflicting properties render the particle neutral so that it interacts very weakly with its environment.

This aloofness has spurred scientists to search for ways to engineer the Majorana into materials, which could provide a much more stable way of encoding quantum information, and thus a new basis for quantum computing.

Yazdani noted that the observation of the Majorana fermion bound within a material is different for physicists than the much publicised discovery of particles, such as the Higgs boson, in a vacuum in giant accelerators.
In such experiments, scientists collide particles at high speeds, producing a shower of free and ephemeral components.
In materials, by contrast, the existence of a particle depends on - or emerges from - the collective properties of atoms and forces surrounding it.

By controlling these interactions, the researchers said, their Majoranas appeared "clean and removed from any spurious particles," which would be unavoidable in high-energy accelerator experiments.
"This is more exciting and can actually be practically beneficial because it allows scientists to manipulate exotic particles for potential applications, such as quantum computing," Yazdani said.
The research was published in the journal Science.