Scientists at the U.S. Department of Energy's Brookhaven National Laboratory (BNL), along with collaborators including Dmitri Kharzeev, a Distinguished Professor of Physics and Astronomy at Stony Brook University, have developed a new method to examine protons using data from high-energy particle collisions.
This approach employs quantum information science to understand how quantum entanglement within protons affects particle tracks from electron-proton collisions. The study reveals that quarks and gluons, which are fundamental components of protons, experience quantum entanglement. Albert Einstein famously described this phenomenon as "spooky action at a distance," where particles can share information about their states even when separated by significant distances. In protons, entanglement occurs over extremely short distances—less than one quadrillionth of a meter—and influences the entire group of quarks and gluons within the proton.
The research team recently published their findings in the journal Reports on Progress in Physics (ROPP). Their six-year effort maps out how entanglement impacts the distribution of stable particles formed after quarks and gluons collide and coalesce into new composite particles.
This perspective on entanglement among quarks and gluons adds complexity to the understanding of protons' internal structure. It may also provide insights into other scientific areas where entanglement is relevant.
For this study, scientists used quantum information science language and equations to predict how entanglement affects particles from electron-proton collisions. This theoretical framework was developed by Kharzeev in 2017 and tested against experimental data in their paper.
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."
Physicist Zhoudunming (Kong) Tu, who joined Brookhaven Lab in 2018 and co-authored the paper, noted that traditional views considered protons as collections of quarks and gluons focused on single-particle properties. He stated, "Now, with evidence that quarks and gluons are entangled, this picture has changed. We have a much more complicated, dynamic system."
The full story is available on the BNL website.