Universal rapidity scaling of entanglement entropy inside hadrons from conformal invariance

TL;DR

This paper demonstrates that the linear rapidity dependence of entanglement entropy inside hadrons is a universal feature arising from conformal invariance, independent of coupling strength, supporting a duality between parton and string models.

Contribution

It shows that the linear rapidity scaling of entanglement entropy is a general consequence of conformal invariance in hadrons, not reliant on weak coupling assumptions.

Findings

Entanglement entropy scales linearly with rapidity in high-energy hadrons.

Conformal invariance explains the universal rapidity dependence.

Supports duality between parton and string descriptions of hadrons.

Abstract

When a hadron is probed at high energy, a nontrivial quantum entanglement entropy inside the hadron emerges due to the lack of complete information about the hadron wave function extracted from this measurement. In the high-energy limit, the hadron becomes a maximally entangled state, with a linear dependence of entanglement entropy on rapidity, as has been found in a recent analysis based on parton description. In this paper, we use an effective conformal field theoretic description of hadrons on the light cone to show that the linear dependence of the entanglement entropy on rapidity found in parton description is a general consequence of approximate conformal invariance and does not depend on the assumption of weak coupling. Our result also provides further evidence for a duality between the parton and string descriptions of hadrons.