Faddeev-Popov ghost
= Faddeev-Popov ghost
{c}
{wiki=Faddeev–Popov_ghost}
= Faddeev-Popov ghost field
{c}
{synonym}
= FP ghost
{c}
{synonym}
A Faddeev-Popov ghost field is a Grassmann-valued scalar field whose Gaussian functional integral represents the <Faddeev-Popov determinant>. Ghosts occur only on internal lines and cancel unphysical gauge-field contributions.