In a new study, physicists at Brown University in the United States observed a new type of quantum particle called "fractional exciton", which is neither a boson nor a fermion, but a particle type in between. This discovery may greatly expand scientists' understanding of the quantum field. The relevant paper was published in the latest issue of Nature magazine.
Researchers say this new particle does not carry an integer charge but follows unique quantum statistical laws. The most exciting thing about it is that it unlocks a series of new quantum phases of matter, opens up new frontiers for scientific research, deepens the understanding of basic physics, and brings new possibilities for quantum computing.
The research focused on the fractional quantum Hall effect, which is based on the classical Hall effect, which involves applying a magnetic field to a material carrying an electric current to produce a transverse voltage. The quantum Hall effect occurs at extremely low temperatures and extremely high magnetic fields, where this transverse voltage increases in clear and independent jumps. In the fractional quantum Hall effect, this increase becomes even more peculiar, only a small part of the electron's charge.
In the experiment, the researchers constructed a structure composed of two layers of the two-dimensional nanomaterial graphene, separated by hexagonal boron nitride insulating crystals. This setup allowed them to precisely control the movement of charges and also generate particles called excitons, which are composed of an electron and a hole combined. Then, in extremely strong magnetic fields millions of times stronger than Earth's, the researchers observed new types of fractional excitons that exhibited unusual behavior.
Generally, elementary particles are divided into two categories: bosons and fermions. Bosons can share the same quantum state, while fermions obey the Pauli exclusion principle, which means that two fermions cannot occupy the same quantum state. However, the fractional excitons observed in experiments do not fit neatly into either of these two categories. Although they have the expected fractional charge, their behavior exhibits characteristics of both bosons and fermions, similar to a hybrid of the two, a particle type in between - anyons, but with unique properties.
This unexpected behavior suggests that fractional excitons may represent an entirely new class of particles with unique quantum properties. Research has shown that excitons can exist in fractional quantum Hall systems, and that some of these excitons are produced by pairing particles with fractional charges, forming fractional excitons that do not behave like bosons.
Researchers point out that this new type of particle may help improve the storage and processing of information at the quantum level in the future, leading to faster and more reliable quantum computers.