Quark and gluon entanglement in the proton based on a light-front Hamiltonian

TL;DR

This paper investigates the quantum entanglement of quarks and gluons inside the proton using light-front Hamiltonian methods, revealing how dynamical gluons influence parton entanglement and suggesting experimental avenues for verification.

Contribution

It introduces a nonperturbative, relativistic calculation of parton entanglement within the proton using Basis Light-front Quantization, including gluon effects.

Findings

Dynamical gluons significantly increase parton entanglement.

Gluons may enhance informational exchange between quarks.

Potential for experimental verification via helicity distribution measurements.

Abstract

Given that the wave function of a proton can be derived relativistically and nonperturbatively from a light-front quantized Hamiltonian, investigating the quantum correlation between quarks and gluons offers a novel perspective on the internal structure of partons within a proton. In this work, we address this topic by computing the spin and longitudinal momentum entanglement of each parton inside the proton. The utilized wave functions are generated using Basis Light-front Quantization (BLFQ), incorporating both the valence quarks and one dynamical gluon Fock sectors, $\left|qqq\right\rangle$ and $\left|qqq\right\rangle +\left|qqqg\right\rangle$. Our calculations indicate that the dynamical gluon significantly enhances entanglement among the proton's partons. Additionally, we examine the spin entanglement of quarks and gluons at fixed values of longitudinal momentum fraction, revealing that the presence of a gluon may amplify the informational exchanges between quarks. Finally, these findings suggest the potential for experimental verification of the entanglement between partons by measuring parton helicity distributions in the proton.