Finding paves way for even better computers

Chinese scientists have discovered new properties of an elusive particle known as Majorana fermion, which has puzzled scientists for more than 80 years, in a more accessible lab environment, paving the way for the next generation of more fault-proof quantum computers.

The particle is named after Italian theoretical physicist Ettore Majorana, who first predicted its existence in 1937. Typically, when a particle－the basic building block of matter－and an antiparticle－its identical twin but with an opposite charge－collide, they will annihilate each other, releasing a burst of energy.

The Majorana fermion, however, is a strange exception that can simultaneously exist as a particle and as its own antiparticle. In 2017, Zhang Shoucheng, a Chinese-American physicist at Stanford University, discovered the fermion using advanced hybrid materials at a temperature close to absolute zero, or-273 C.

The latest discovery was made on iron-based superconductors at a temperature around 4 Kelvin, or -269 C. These requirements are more achievable in common labs using liquid helium, thus reducing the cost of research, Ding Hong, a researcher at the Institute of Physics of the Chinese Academy of Sciences and one of the lead scientists behind the discovery, said on Friday.

Wen Xiaogang, a physicist/professor at the Massachusetts Institute of Technology, said the recent discovery might allow iron-based superconductors to be used in making new quantum computers that are more immune to natural disturbances that could make the machine lose its effectiveness.

Chinese scientists also discovered that in solid matter, a single Majorana fermion can be "captured" and split into two Majorana anyons, Ding said. Anyons are quasiparticles that possess particlelike properties yet do not belong to the family of real particles like protons and neutrons.

The research was published in the journal Science on Friday.

Scientists might be able to use this property to create a new type of quantum computer, called a topological quantum computer, that is more stable than the standard quantum computers currently being researched by tech giants such as Google, IBM and Intel, Ding said.

In March, scientists from Google had tested a world-leading quantum computer processor with 72 quantum bits, or qubits, for data storage and calculations.

Qubits are subatomic particles that can be both 1 and 0 at the same time, unlike conventional computers, including supercomputers, which can only store data in 1 or 0 binary bits.

This strange phenomenon is called quantum superposition. Thanks to this effect, quantum computers' computing power can increase astronomically as the number of qubits used increases, said Zhang Fuchun, a physics professor at the University of Chinese Academy of Sciences.

"However, qubits in today's standard quantum computers are prone to natural disturbances, and can easily lose their data and functions," Zhang said. "So scientists need to protect a single qubit with a hundred other particles, and keep them all at extreme conditions. These can significantly drive up design difficulties and costs."

Since each Majorana fermion can behave like half of a subatomic particle, a single qubit could theoretically be stored in two separated fermions, decreasing the chance of both fermions being disturbed and losing their data, he said.