Bethe-Salpeter equation on the light-front

The Bethe-Salpeter equation on the light-front for the two boson bound state with up to four particles in the intermediate state is constructed from the covariant equation in the ladder approximation. The interaction corresponds to the exchange of an intermediate boson between the other two. The light-front Bethe-Salpeter equation is equivalent to the covariant one in the ladder approximation if intermediate states with any number of exchanged bosons are allowed in the kernel. We made numerical calculations allowing up to four-particle intermediate states to study the effect of the high Fock state components in the bound two-boson systems. (author)