Entanglement saturation in quantum electrodynamics scattering processes

TL;DR

This paper studies how two-particle QED scattering processes lead to maximal entanglement through repeated filtering, revealing a universal saturation behavior especially for massive fermions, with partial effects for photons.

Contribution

It demonstrates that QED scattering processes can be modeled as dynamical quantum maps that produce maximal entanglement after infinite iterations, highlighting a structural property of these maps.

Findings

Maximal entanglement is achieved after infinite iterations for massive fermions.

Photon processes show partial entanglement saturation depending on the specific process.

The structure of the quantum maps explains the entanglement saturation phenomenon.

Abstract

We investigate the properties of quantum electrodynamics (QED) two-particle scattering processes when an arbitrarily sharp filtering of the outgoing particles in momentum space is performed. We find that these processes are described by dynamical quantum maps, whose structure is such that any initial state is transformed into a maximally entangled state, after an infinite number of iterations of the map. This structural property is exactly realized if all the colliding particles are massive fermions while, when photons are involved, it is verified in a partial way, depending on the process under consideration.