The braiding of Majorana zero modes is depicted here. (Photo : Li et. al)
A research team from the Key Laboratory of Quantum Information of the Chinese Academy of Sciences has reported success in the fabrication and manipulation of Majorana zero modes (MZMs) in an optical simulator.
The team led by professors Li Chuangfeng; Xu Jinshi and Han Yongjian implemented the exchange of two MZMs in which the non-Abelian statistics of MZMs were supported.
Majorana fermions were first proposed by Italian physicist Ettore Majorana in 1937. Majorana fermions are fermions whose antiparticles are identical as themselves.
This kind of fermions is vital to the research of superconducting materials and topological quantum computation. Eighty years after their proposed existence, however, Majorana fermions have eluded discovery.
Although it's widely proposed that neutrinos are Majorana fermions, there is still no evidence to support this conjecture. In condensed matter physics, however, scientists have discovered quasiparticles -- Majorana zero modes (MZMs) -- that have characteristics similar to Majorana fermions.
Generally, the statistics of the identical particles can be determined by their exchange characters. For example, the internal quantum states remain the same when two bosons are exchanged, while they would be imposed by a \pi phase when two fermions are exchanged.
The bosons and fermions belong to particles with more general statistics, which are called Abelian anyons. A global phase (not necessary 0 or \pi) is gained after the exchange of two identical Abelian anyons.
Moreover, there may exist some exotic particles, named non-Abelian anyons, which will undertake an unitary transformation (not just a global phase) after exchange. The Majorana fermions with their own antiparticles are widely believed to be the non-Abelian particles.
The research team took the advantage of the quantum simulation approach. This means that while the simulated system is not experimentally accessible with current technology, the quantum simulator and its measurement results provide information about the simulated system.
In their work, the team designed a set of dissipative processes that can effectively create and transfer the MZMs supported in the Kitaev model.
They finally completed the exchange of two MZMs. The measured Berry phase during the exchange process supports the non-Abelian statistics of MZMs.
Furthermore, they demonstrated that the information encoded in the MZMs is immune to local noises in the linear optical system.
This method provides a novel way to study quantum statistics; topological quantum computation and the characters of MZMs.
This achievement also establishes a promising platform to investigate the properties of the MZM in complex architectures and the topological quantum computation based on the MZMs.
Their work was published in the scientific journal, Nature Communications, on October 25.
