The physics of critical phenomena is the physics of systems close to a critical point, like the critical temperature in a ferromagnetic transition or the critical point of a gas-liquid transition. Examples of critical phenomena include dynamical slowing down, divergence of correlation length and ergodicity breaking.

The term critical phenomena refers to the behavior of physical systems close to a critical point. Well-known examples are the critical temperature of a ferromagnetic transition and the critical $(P,T)$ point of a liquid-gas transition.

The term critical phenomena is thus usually associated to continuous (second-order) phase transitions. Examples of critical phenomena occurring during second-order phase transitions are:

  • Dynamical slowing down
  • Divergence of the correlation length
  • Emergence of scaling laws
  • Power-law divergence of physical quantities (like the magnetic susceptibility $\chi$ in a ferromagnetic phase transition)
  • Ergodicity breaking
  • Emergence of fractal structures