Nonlinear Sigma Model

The Nonlinear Sigma Model is a mathematical framework used in physics to describe how certain fields or particles behave when constrained to move on curved surfaces or spaces. Instead of freely varying in all directions, these fields are limited to follow specific pathways defined by a curved geometry, like points on a sphere. This model helps scientists understand complex systems, such as magnetic spins in materials or fundamental particles in high-energy physics, by capturing the effects of symmetry and geometry on their interactions without assuming linear, straightforward behavior.