Quantum spin liquids are fascinating magnetic states where spins do not order even at zero temperature. This happens because quantum fluctuations randomize spins, establish intricate quantum entanglement among them and lead to many other remarkable quantum phenomena. In 2006, theoretical physicist Alexei Kitaev proposed an exactly solvable model of a quantum spin liquid and suggested its potential application in quantum information technology. Surprisingly, it was later shown that this theoretical model - the Kitaev spin liquid – might be realized in heavy transition metal ion materials. Recently, new materials have been synthesized and much effort spent to gather experimental evidence for a quantum spin liquid and in particular, its defining feature of spin fractionalization. For theorists this provides a unique opportunity to explore the characteristic fingerprints of quantum spin liquid physics on a more quantitative level.
