{title2=$\mathcal L=\tfrac12\partial_\mu\phi\partial^\mu\phi-V(\phi)$}
{wiki}

A scalar field theory describes one or more <Lorentz scalar> fields through an <action>. The displayed <Lagrangian density> is a common classical normalization for a <real scalar field>; a <complex scalar field> has two real components. <Canonical quantization> turns these classical degrees of freedom into operators. The free <real scalar field> gives spin-zero particles, while interactions arise from the potential $V$.


 Scalar field theory (source code)