Quantum spin liquids are unusual magnetic phases in which spins remain disordered even near absolute zero.

In an ordinary magnet, standard excitations are called magnons, collective waves in which many atomic spins tilt together. Spinons, however, are stranger, They are emergent quasiparticles that arise from the coordinated behaviour of many strongly interacting spins.

In quantum spin liquids, quantum entanglement allows these spinons to separate and propagate without immediately recombining. Although a conventional magnon carries spin 1, two independently moving spinons can each carry spin 1/2. This process is called fractionalisation. Generally spinons are produced in combinations that preserve the system’s overall quantum numbers.

These properties make quantum spin liquids useful for investigating fundamental ideas including entanglement, fractionalisation and particle confinement. Some may also inspire future approaches to quantum computing, magnetic devices and the transport or storage of quantum information, although practical applications remain a long-term prospect.

Researchers have often expected confinement, which prevents spinons from moving independently, to suppress exotic quantum behaviour. However, a new study shows that this is not necessarily the case. The team found that Polyakov confinement can transform a Dirac quantum spin liquid into a symmetry-protected topological state.

Although the spinons can no longer move freely through the new state’s interior, unusual and protected spin behaviour remains along its edges. The researchers supported this claim using field theory and variational Monte Carlo simulations.

The team also suggested that this state could arise in a model magnet with spins arranged on a triangular lattice. Their calculations predict that applying a weak magnetic field would produce a recognisable redistribution of spin near the edges, offering a possible way to detect the state experimentally.

Ultimately, the study shows that unusual quantum effects can survive in unexpected ways, even when the particles responsible for them become trapped.