In a one-dimensional optical lattice, potassium-39 atoms dressed in Raman fields behave as if they exchange not an integer but a fractional phase shift — like particles that do not exist in nature. A team at ICFO in Barcelona (Spain) has proposed a model in which bosons acquire density-dependent Peierls phases when tunneling through occupied sites.
In a preprint dated 6 November 2026, the physicists Josep Cabedo, Claudio Iacovelli, Leticia Tarruell and Alessio Celi showed that loading Raman-coupled 39K atoms into a one-dimensional lattice realizes a lattice analogue of chiral BF theory. At a small statistical phase the model reduces to the known anyon-Hubbard model, and beyond it a new version arises with unbounded rather than periodic interactions. Numerical calculations confirmed the key signatures of one-dimensional anyons: a density-dependent asymmetry of the momentum distribution in the ground state, asymmetric transport under the action of interactions, and chiral bound states.
Imagine a line along which particles move: each time one "passes" another, it receives an additional phase rotation proportional to the number of neighbors it has already encountered. In the ordinary world bosons pass without a trace, fermions with hard repulsion; here, by contrast, the phase accumulates gradually, as in a tangled braid, and changes the direction of motion of the whole system.
This opens the way to the experimental study of anyons beyond a few particles — using existing setups with Raman-coupled potassium atoms. Asymmetric transport and chiral states could become resources for topological quantum computing or for simulating quantum fields with fractional statistics.
According to the preprint on arXiv dated 6 November 2026, all the listed effects are accessible for direct observation in the laboratory. The model requires no exotic conditions and relies on proven methods of laser cooling and optical lattices.
One-dimensional anyons cease to be a purely theoretical abstraction and become a controllable platform for testing the fundamental laws of quantum statistics.
