Suffolk Reporter

Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory, along with collaborators, have developed a new method to study protons using data from high-energy particle collisions. Their approach applies quantum information science to explore how particle tracks from electron-proton collisions are influenced by quantum entanglement within the proton.

The findings reveal that quarks and gluons, which form the fundamental structure of protons, experience quantum entanglement. This phenomenon was described by Albert Einstein as "spooky action at a distance," where particles can share states like spin direction over significant distances. In this case, entanglement occurs over extremely short distances within individual protons.

The team's recent paper in Reports on Progress in Physics outlines their six-year research project mapping how entanglement affects stable particles' distribution after quarks and gluons coalesce into new composite particles following collisions.

Physicist Zhoudunming (Kong) Tu remarked, “Before we did this work, no one had looked at entanglement inside of a proton in experimental high-energy collision data.” He added that their work provides a more complex view of proton structure due to evidence of quark and gluon entanglement.

Future experiments at Brookhaven Lab's upcoming Electron-Ion Collider will build on these insights to examine other nuclear physics questions such as how larger nuclei affect proton properties. The researchers used equations from quantum information science to predict how entangled particles should behave post-collision—a method initially proposed by Dmitri Kharzeev and Eugene Levin.

Kharzeev explained, “For a maximally entangled state of quarks and gluons, there is a simple relation that allows us to predict the entropy of particles produced in a high energy collision.” This prediction was tested against data from past HERA experiments and matched perfectly with theoretical expectations.

These findings could simplify understanding complex nuclear physics phenomena by focusing on collective behaviors rather than intricate individual interactions. Tu noted that exploring the statistical behavior offers insights similar to observing boiling water's temperature without knowing each molecule's motion.

Looking ahead, scientists aim to apply their model further—particularly examining how embedding protons within nuclei impacts their properties. As Tu stated, “It will be very helpful to use the same tools to see the entanglement in a proton embedded in a nucleus.”

Martin Hentschinski highlighted that studying nuclear environments' effects on protons is central to EIC science goals. Krzysztof Kutak emphasized using this tool for broader studies could advance understanding visible matter structures.

Funding for this research came from several sources including DOE Office of Science and European Union’s Horizon 2020 program among others.