'Spooky action' at a very short distance: Scientists map out quantum entanglement in protons

Amazing stuff!

"... The results reveal that quarks and gluons, the fundamental building blocks that make up a proton's structure, are subject to so-called quantum entanglement. This quirky phenomenon, famously described by Albert Einstein as "spooky action at a distance," holds that particles can know one another's state—for example, their spin direction—even when they are separated by a great distance. ...

This new view of entanglement among quarks and gluons adds a layer of complexity to an evolving picture of protons' inner structure. It may also offer insight into other areas of science where entanglement plays a role. ...

"Before we did this work, no one had looked at entanglement inside of a proton in experimental high-energy collision data," ..."

"... The revelation of entanglement among quarks and gluons sheds light on the nature of their strong-force interactions ... It may offer additional insight into what keeps quarks and gluons confined within protons, which is one of the central questions in nuclear physics that will be explored at the EIC.

“Maximal entanglement inside the proton emerges as a consequence of strong interactions that produce a large number of quark-antiquark pairs and gluons,” he said.

Strong-force interactions — the exchange of one or more gluons among quarks — take place between individual particles. That may sound just like the simplest description of entanglement, where two individual particles can know about one another no matter how far apart they are. But entanglement, which is really an exchange of information, is a system-wide interaction.

“Entanglement doesn’t only happen between two particles but among all the particles,” ..."

From the abstract:

"Entanglement entropy has emerged as a novel tool for probing nonperturbative quantum chromodynamics (QCD) phenomena, such as color confinement in protons. While recent studies have demonstrated its significant capability in describing hadron production in deep inelastic scatterings, the QCD evolution of entanglement entropy remains unexplored. In this work, we investigate the differential rapidity-dependent entanglement entropy within the proton and its connection to final-state hadrons, aiming to elucidate its QCD evolution. Our analysis reveals a strong agreement between the rapidity dependence of von Neumann entropy, obtained from QCD evolution equations, and the corresponding experimental data on hadron entropy. These findings provide compelling evidence for the emergence of a maximally entangled state, offering new insights into the nonperturbative structure of protons."

'Spooky action' at a very short distance: Scientists map out quantum entanglement in protons

'Spooky Action' at a Very Short Distance: Scientists Map Out Quantum Entanglement in Protons (original news release) "Particles streaming from collisions offer insight into dynamic interactions and collective behavior of quarks and gluons"

QCD evolution of entanglement entropy (no public access)

QCD evolution of entanglement entropy (pre-print, open access)