Mohsen Emami-Razavi - Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran, Iran
Somayeh Asgary - Department of Physics, West Tehran Branch, Islamic Azad University, Tehran, Iran

The variational method within the Hamiltonianformalism of QFT using Darewych reformulated modelhas been used for scalar particles and antiparticlesinteracting through a scalar mediating field. We haveinvestigated the relativistic effects such as virtual annihilationinteractions and retardation effects for relativistictwo-, four-, and six-body wave equations inscalar QFT. Approximate ground-state solutions havebeen studied for different strengths of coupling, for bothmassive and massless mediating fields where the virtualannihilation terms or retardation effects in the waveequations have been included or eliminated.

Relativistic Wave equations Bound state Virtual annihilation interactions Retardation effects