Lee-Yang theorem

The Lee-Yang theorem is a result in physics that explains how certain mathematical points, called zeros, relate to phase transitions—like water turning to ice. It states that, for some models of magnetism, these zeros of a specific mathematical function (the partition function) lie on a particular circle in the complex plane. As the system's size grows, these zeros approach the real number line, indicating a phase change. This understanding helps physicists connect the mathematical properties of a system to observable phenomena, like magnetization changes, by analyzing where these zeros occur.