Researchers from the University of Innsbruck, the Collège de France, and the Université Libre de Bruxelles have developed a simple yet powerful method to reveal anyons-exotic quantum particles that are neither bosons nor fermions-in one-dimensional systems.
In conventional three-dimensional space, particles belong to one of two categories: fermions or bosons. In low-dimensional settings, however, quantum mechanics allows for more exotic behavior. Here, anyons can emerge-quasi-particles whose exchange properties continuously interpolate between those of bosons and fermions, leading to fractional statistics. Detecting and engineering such particles in one dimension has long been a central challenge, typically requiring, as theory proposal suggest, intricate scattering schemes or density-dependent tunneling processes.
A new study by teams led by Hanns-Christoph Nägerl at the University of Innsbruck and Nathan Goldman at the Université Libre de Bruxelles and Collège de France (CNRS) now introduces a remarkably simple yet powerful approach. The researchers propose an effective "swap" model that leverages the spin degree of freedom of ultracold atoms. By assigning a complex phase to the exchange-or "swap"-of two spins, the system naturally acquires the fractional statistical behavior characteristic of anyons.
The team shows that this mechanism directly imprints itself on the one-body correlations of a single spin component. These correlations reveal the asymmetric momentum distributions predicted for one-dimensional anyons-signatures that remained hidden in conventional bosonic observables. The framework captures the essence of recent experimental observations of anyonization in ultracold gases and provides a route for implementing and probing such phenomena in current laboratory setups.
"By highlighting the central role of spin-exchange processes, the work opens new perspectives for exploring many-body anyonic physics and deepens our understanding of exotic quantum behavior in low-dimensional systems", summarizes Hanns-Christoph Nägerl.
Publikation: Anyonization of bosons in one dimension: an effective swap model. Botao Wang, Amit Vashisht, Yanliang Guo, Sudipta Dhar, Manuele Landini, Hanns-Christoph Nägerl, Nathan Goldman. Phys. Rev. Lett. 2025. DOI: 10.1103/2np8-mp39
