In quantum physics, subatomic particles behave strangely—they can be in two places simultaneously, move through solid objects, and communicate instantly over long distances. Scientists are studying these behaviors to understand the quantum world better.
Physicists at Brown University have discovered a new type of quantum particle called fractional excitons. These particles have surprising behaviors and could greatly expand our understanding of quantum physics.
They do not carry any overall charge but follow unique quantum rules, which could lead to new phases of matter, advanced research, and improved quantum computation.
The team’s discovery focuses on the fractional quantum Hall effect, which is based on the classical Hall effect. In the classical Hall effect, a magnetic field applied to a material with an electric current creates a sideways voltage.
The quantum Hall effect happens at very low temperatures and high magnetic fields, causing this voltage to increase in clear steps. In the fractional quantum Hall effect, these steps increase by fractional amounts, carrying a fraction of an electron’s charge.
New approach to exotic quantum matter
Researchers used two thin layers of graphene, separated by an insulating layer of hexagonal boron nitride, to control electrical charges and create excitons—particles made by combining an electron and a missing electron (a hole). Exposing this setup to extremely strong magnetic fields, they observed the new fractional excitons, which behaved surprisingly.
Fundamental particles usually fall into two types: bosons, which can share the same quantum state, and fermions, which follow the Pauli exclusion principle, meaning no two fermions can be in the same quantum state.
The fractional excitons didn’t fit neatly into either category, but they showed features of both and acted like a mix of the two. This made them similar to anyons, a type of particle between fermions and bosons, but with unique properties.
Naiyuan Zhang, a study co-author, said these unexpected behaviors suggest fractional excitons could represent a new class of particles with unique quantum properties.
The discovery could improve how information is stored and used at the quantum level, leading to better quantum computers. Jia Li said this discovery opens new ways to explore and use the phenomenon, and the team will now study how these fractional excitons interact and if their behavior can be controlled.
Dima Feldman added that this discovery gives a new understanding of quantum mechanics.
Journal Reference:
- Zhang, N.J., Nguyen, R.Q., Batra, N. et al. Excitons in the fractional quantum Hall effect. Nature 637, 327–332 (2025). DOI: 10.1038/s41586-024-08274-3
Source: Tech Explorist
