Effects of photon field on entanglement generation in charged particles

TL;DR

This paper investigates how photon field interactions influence entanglement between charged particles, revealing suppression due to vacuum fluctuations and potential parallels with quantum gravity effects.

Contribution

It derives the first formula for entanglement negativity of charged particles coupled to a photon field using covariant QED, highlighting quantum superposition effects.

Findings

Entanglement is suppressed by photon vacuum fluctuations.

Quantum superposition of bremsstrahlung affects entanglement negativity.

Similar structures between electromagnetic and gravity theories suggest analogous entanglement features.

Abstract

The Bose-Marletto-Vedral (BMV) experiment [3, 4] is a proposal for testing the quantum nature of gravity with entanglement due to Newtonian gravity. This proposal has stimulated controversy on how the entanglement due to Newtonian gravity is related to the essence of quantum gravity and the existence of gravitons. Motivated by this, we analyze the entanglement generation between two charged particles coupled to a photon field. We assume that each particle is in a superposition of two trajectories and that the photon field is initially in a coherent state. Based on covariant quantum electrodynamics, the formula for the entanglement negativity of the charged particles is derived for the first time. Adopting simple analytic trajectories of the particles, we demonstrate the entanglement between them. It is observed that the entanglement is suppressed by the decoherence due to the vacuum fluctuations of the photon field. We also find that the effect of quantum superposition of bremsstrahlung appears in the entanglement negativity formula. The similar structures between the gravity theory and electromagnetic theory suggests that a similar feature may be observed in the entanglement generation by quantum gravitational radiation.