Phys. Rev. Lett. 118, 227201 (2017)

Particles are usually categorized as being either bosons or fermions, obeying Bose–Einstein or Fermi–Dirac statistics. When dealing with two-dimensional systems, however, quasiparticles known as anyons can emerge, whose statistics lie somewhere between the two. As they can exhibit non-Abelian behaviour, researchers are looking to exploit anyons for topological quantum computation. But experimentally, just seeing these quasiparticles is far from easy. Siddhardh Morampudi and colleagues have now shown that signatures of anyons could be detected using established techniques such as neutron scattering or tunnelling spectroscopy.

In certain materials, scattering processes can create fractionalized quasiparticle excitations. Morampudi et al. showed that if such quasiparticles have anyonic statistics, and you're near the threshold energy for their excitation, then the scattering cross-sections should exhibit a distinct power law whose exponent depends only on the statistics of the anyons. This threshold spectroscopy-based approach provides a clear route for looking for anyonic excitations in topologically ordered materials such as gapped quantum spin liquids. But these ideas may also be applicable to ultracold atoms in optical lattices — greatly expanding the list of candidate systems to explore.