  We report on a systematic study on the entanglement between helicity degrees
of freedom generated at tree-level in quantum electrodynamics two-particle
scattering processes. We determine the necessary and sufficient dynamical
conditions for outgoing particles to be entangled with one another, and expose
the hitherto unknown generation of maximal or nearly maximal entanglement
through Bhabha and Compton scattering. Our work is an early step in revisiting
quantum field theory and high-energy physics in the light of quantum
information theory.
