Quartic interaction

In physics, particularly in quantum field theory and statistical mechanics, interactions among particles are often characterized by the types of terms in the Lagrangian or Hamiltonian that describe the system. A "quartic interaction" refers to a term in the theory that involves four fields or four particles interacting with each other simultaneously. Mathematically, a quartic interaction can take the form of a term in the Lagrangian that is proportional to the product of four fields.