Collective Excitations

Collective excitations are coordinated movements within a material where many particles, like atoms or electrons, act together rather than individually. Instead of each particle moving randomly, they follow organized patterns—such as waves or oscillations—that propagate through the substance. Examples include sound waves in air or vibrations in a crystal lattice. These collective behaviors reveal important properties of materials, like how they conduct heat or electricity, and provide insight into their underlying structure and dynamics.