The Ginzburg–Landau Equation is a mathematical model used to describe phase transitions in various physical systems, particularly in superconductivity. It provides a framework for understanding how materials change from one state to another, such as from a normal state to a superconducting state, by using an order parameter that represents the density of superconducting pairs. This equation is derived from Ginzburg and Landau's theory, which combines thermodynamics and quantum mechanics. It captures the behavior of the order parameter in response to external factors like temperature and magnetic fields, allowing scientists to predict phenomena such as vortex formation in superconductors.