University of Adelaide’s Dr. Ross Young and colleagues from the QCDSF Collaboration are exploring the structure of subatomic matter to try and provide further insight into the forces that underpin the natural world. Their result is possibly the smallest-ever force field map of nature ever generated.
Distribution of the color-Lorentz force acting on an unpolarized up quark in the transverse plane (indicated by the vector field) superimposed on the up quark density distribution in impact-parameter space for an unpolarized proton. Image credit: Crawford et al., doi: 10.1103/PhysRevLett.134.071901.
“We have used a powerful computational technique called lattice quantum chromodynamics to map the forces acting inside a proton,” Dr. Young said.
“This approach breaks down space and time into a fine grid, allowing us to simulate how the strong force — the fundamental interaction that binds quarks into protons and neutrons — varies across different regions inside the proton.”
“Our findings reveal that even at these minuscule scales, the forces involved are immense, reaching up to half a million Newtons, the equivalent of about 10 elephants, compressed within a space far smaller than an atomic nucleus,” said University of Adelaide Ph.D. student Joshua Crawford.
These force maps provide a new way to understand the intricate internal dynamics of the proton, helping to explain why it behaves as it does in high-energy collisions, such as those at CERN’s Large Hadron Collider, and in experiments probing the fundamental structure of matter.
“Edison didn’t invent the light bulb by researching brighter candles — he built on generations of scientists who studied how light interacts with matter,” Dr. Young said.
“In much the same way, modern research such as our recent work is revealing how the fundamental building blocks of matter behave when struck by light, deepening our understanding of nature at its most basic level.”
“As researchers continue to unravel the proton’s inner structure, greater insight may help refine how we use protons in cutting-edge technologies.
“One prominent example is proton therapy, which uses high-energy protons to precisely target tumors while minimizing damage to surrounding tissue.”
“Just as early breakthroughs in understanding light paved the way for modern lasers and imaging, advancing our knowledge of proton structure could shape the next generation of applications in science and medicine.”
“By making the invisible forces inside the proton visible for the first time, this study bridges the gap between theory and experiment — just as earlier generations uncovered the secrets of light to transform the modern world.”
A paper describing the team’s results was published in the journal Physical Review Letters.
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J.A. Crawford et al. 2025. Transverse Force Distributions in the Proton from Lattice QCD. Phys. Rev. Lett 134, 071901; doi: 10.1103/PhysRevLett.134.071901
