Amazing stuff! How exciting! It appears that two similar papers were published on the same day in Nature. See also my blog post here.
"In a new study ... observed a novel class of quantum particles called fractional excitons, which behave in unexpected ways and could significantly expand scientists' understanding of the quantum realm.
"Our findings point toward an entirely new class of quantum particles that carry no overall charge but follow unique quantum statistics," ..."
"... In their experiments, the researchers built a structure with two thin layers of graphene, a two-dimensional nanomaterial, separated by an insulating crystal of hexagonal boron nitride. This setup allowed them to carefully control the movement of electrical charges. It also allowed them to generate particles known as excitons, which are formed by combining an electron and the absence of an electron known as a hole. They then exposed the system to incredibly strong magnetic fields that are millions of times stronger than Earth's. This helped the team observe the novel fractional excitons, which showed an unusual set of behaviors. ..."
From the abstract::
"Excitons, Coulomb-driven bound states of electrons and holes, are typically composed of integer charges. However, in bilayer systems influenced by charge fractionalization, a more interesting form of interlayer exciton can emerge, in which pairing occurs between constituents that carry fractional charges. Despite numerous theoretical predictions for these fractional excitons, their experimental observation has remained unexplored.
Here we report transport signatures of excitonic pairing in fractional quantum Hall effect states. By probing the composition of these excitons and their impact on the underlying wavefunction, we discover two new types of quantum phases of matter. One of these can be viewed as the fractional counterpart of the exciton condensate at a total filling of 1, whereas the other involves a more unusual type of exciton that obeys non-bosonic quantum statistics, challenging the standard model of bosonic excitons."
Discovery of new class of particles could take quantum mechanics one step further (original news release) "A study led by a team of Brown University researchers could lead to new ways of exploring quantum phenomena, with implications for future advances in technology and computing."
Excitons in the fractional quantum Hall effect (no public access)
Excitonic pairing and fractional quantum Hall effect in quantum Hall bilayer.
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