New theory suggests spin models can all be mathematically unified

Science : Spin models, which were developed in 1920 by Wilhelm Lenz and analyzed by his student Ernst Ising, explain the behavior of atoms in magnetic materials. Ising showed that atoms can interact with their neighbors to form pairs such that, if their spins point in the same direction, the paired atoms reach a lower energy state. Ising was able to show that a 1D string of spins does not experience a temperature-driven phase transition, in which all the atoms suddenly point the same direction. In 1944, Lars Onsager was able to show that a specific 2D version of the Ising spin model does experience that phase transition. Other scientists advanced spin models and even applied them to problems outside of physics. Now, Gemma De las Cuevas of the Max Planck Institute of Quantum Optics in Garching, Germany, and Toby Cubitt of University College London say they have shown that all of those other spin models can be translated into a single version of the 2D Ising model. In their paper, they argue that both the 2D Ising model and all other spin models can be translated into a logical structure known as the satisfiability, or SAT, problem . That functional equivalence opens up the possibility of creating simpler simulations of complex spin models. However, because the general form of the 2D Ising model is still unsolved, how easy that will be to do is unclear.