Quartic interaction

This article refers to a type of self-interaction in scalar field theory, a topic in quantum field theory. Other types of quartic interactions may be found under the topic of four-fermion interactions. A classical free scalar field ${\displaystyle \varphi }$ satisfies the Klein–Gordon equation. If a scalar field is denoted ${\displaystyle \varphi }$, a quartic interaction is represented by adding a potential term ${\displaystyle {\frac {\lambda }{4!}}\varphi ^{4}}$. The coupling constant ${\displaystyle \lambda }$ is dimensionless in 4-dimensional spacetime.

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