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The ARC Special Research Centre for the Subatomic Structure of Matter  

Enquiries: +61 8 8313 3533  

Location: Level 1, Physics Building, University of Adelaide, Adelaide, SA  

Mailing Address: CSSM, Rm. 126, Lvl 1 Physics Building, University of Adelaide, SA 5005, Australia  
The University of Adelaide

Wake up… Wake up… You’ve been living in a dream world. A classical world of solid objects, bouncing balls and Newton’s laws. It is the world that you see, but your eyes have been veiled from the truth.

The truth is that behind the classical world lies a hidden world, the quantum world. You may see a solid wall in front of you, but if you could look closer you would see the molecules that form the wall. Closer still and the atoms which make up the molecules would come into view. Look even closer and you will perceive the protons, neutrons and electrons which form those atoms, and the strange quantum world they live in. A world where nothing is certain, and particles can be in two places at once. A world where the act of looking changes what is there.

If your eyes could perceive at a scale smaller than the protons and the neutrons, you would see that they are made up of smaller particles. These subatomic particles are quarks, and they are born into bondage. The force which binds the protons and neutrons in the atom is in fact merely a remnant of the strong interaction which the quarks experience. The strong interaction is mediated by particles called gluons, and the force with which they bind the quarks together is so strong that they are destined to remain trapped by their gluonic captors, except at the highest energies where quarks are liberated into the quark-gluon plasma.

The theory which describes quarks and gluons is Quantum Chromodynamics (QCD). It is a highly complex theory which is extremely difficult to solve. While there are many models which can used to study QCD, the only known way to study the theory without approximations is to place space-time on a four dimensional lattice, so that the theory can be simulated on a computer. This is what we call Lattice QCD, and it is computationally demanding, requiring the use of cutting-edge supercomputers.

The images on this poster were made using Lattice QCD. What is the lattice? Exploring the strange world of quantum physics, or playing with some of the fastest supercomputers in the world are part of the answer. To find out the rest, you must experience it for yourself. How you ask? Study physics at the University of Adelaide and be a part of the Centre for the Subatomic Structure of Matter.

Quick Facts:

Strong Nuclear Force

Of the four basic forces of nature including the strong nuclear force, the electromagnetic force, the weak nuclear force and gravity, the nuclear force is the strongest. However, it has a very short range and therefore the particles must be close before it is effective. Ultimately its purpose is to hold together the subatomic particles of the nucleus


Any of a group of six elementary particles having electric charges of a magnitude one-third or two-thirds that of the electron. They are the building blocks of matter.


A massless, neutralcharge elementary particle which mediates the strong interaction and binds quarks to form hadrons like the proton.

Quantum Chromodynamics

In addition to electric charge, quarks possess a type of charge called colour charge. Particles with colour charge experience the strong interaction, which is mediated by the gluon field. The theory which describes the strong interactions between quarks and gluons is called Quantum Chromodynamics, or QCD for short.

Lattice QCD

While the gluons are the particles which carry the strong force, they themselves possess colour charge. This means that the gluons interact with each other as well as the quarks. This property of QCD makes it extremely complex, and one of the best ways to study QCD is on the Lattice, where the theory is formulated on a space-time box simulated on supercomputers.

Lattice QCD Visualisation


A snapshot of the QCD vacuum showing that empty space is not really empty. This is a gluon field. This is what you would see when you stare into empty space if you could see gluons. The red hot spots indicate where the gluon field is strong. Isolated lumps correspond with the knotted-winding nature of the gluon field.

The topological charge density or winding density of a gluon field. The energy fluctuations of the gluon field illustrated at top correspond with the localised winding. Gluons can wind in positive (red to yellow) and negative (blue to green) directions.

The Proton

The red, green and blue spheres are quarks, confined by the gluon field to form a proton. The pair of green and magenta (anti-green) spheres are a quark-antiquark pair, forming a meson. The quarks only make up 3% of the proton’s mass, and the gluon field makes up 97% by Einstein’s equation m = E/c2. Hence, the majority of all mass originates in gluon interactions. The white line depicts a scattered electron fired at the proton, to probe its structure.

Topological charge density of a single gluon field configuration.

Quark eigenmode density on the same configuration. Note that the quark field is localised on a topological object, indicating the quark field and topological fields are correlated.



Is a high performance compute cluster from Sun Microsystems. When it was installed in June 2000 it was the fastest supercomputer in the Southern Hemisphere and ranked #188 in the 500 top super computers of the world. It’s primarily used for Lattice QCD calculations.


Is also located at the University of Adelaide. Hydra ranked #106 in the 500 top supercomputers of the world in June 2003. Hydra is used for computational physics (including Lattice QCD), chemistry, biotechnology, engineering, geoscience, petroleum engineering, applied mathematics, water resource management and computer fluid dynamics.

The expulsion of the QCD vacuum from the region between a quark-antiquark pair. The tube joining the two quarks reveals the positions in space where the vacuum action is maximally expelled and corresponds to the famous "flux tube" of QCD.

Free fonts used with permission. “Matrix” TrueType font ©Charlotte Iona Dymock, 2000. “Miltown” TrueType font ©Apostrophe, 2000. Poster design and content by Brigitte Kamleh and Waseem Kamleh. Images generated by Derek Leinweber. Caption content sourced from Derek’s webpage. Some definitions sourced from http://Dictionary.com/ and http://aether.lbl.gov/.

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