Two-body Dirac equations

The two-body Dirac equation is an extension of the Dirac equation, which describes relativistic particles with spin-1/2 (such as electrons) in quantum mechanics. The original Dirac equation provides a theoretical foundation for understanding the behavior of single particles in a relativistic framework and captures phenomena such as spin and antimatter. When dealing with two-body systems, such as two interacting particles (like an electron and a positron), the situation becomes more complex.