By extending a proof of a physically important behavior in one-dimensional quantum spin systems to higher dimensions, a RIKEN physicist has shown in a new study that the model lacks exact solutions. The research is published in the journal Physical Review B.

Theoretical physicists develop mathematical models to describe material systems, which they can then use to make predictions about how materials will behave.

One of the most important models is the Ising model, which was first developed about a century ago to model magnetic materials such as iron and nickel.