Our existence, as well as our ability to touch and interact with the universe around us, is governed by the collisions of atoms and molecules. The constant jostling and vibrating of these particles give us heat, light, and life.
Professor Igor Bray and his team at Curtin University’s Department of Physics and Astronomy are using supercomputers to chart movement at the atomic scale and unlock the amazing power possessed by these atoms.
Particle collisions happen on a scale that is both microscopic and complex. Many millions of particles will collide at each moment, transferring energy and sometimes emitting new particles. It is only in the past few years that Professor Bray’s team has had the computing power to deal with the more complex interactions of molecules.
“You can start off with an atom. It’s a sphere, so the forces will be symmetrical on all sides. But then you move to molecules – even the simplest molecule, H2 loses that symmetry,” said Professor Bray. “H2 molecules orient in one direction. On top of that, they’re now a molecule instead of an atom. So they’ll also vibrate, which is another dimension.
It becomes a much more complicated calculation.” While Professor Bray’s team have set their eyes on larger molecules, the industries that use their work demand exact calculations. The new technologies exist in energy, medicine, and astronomy. So calculations must be surgically precise.
To meet the demanding levels of computing power required for calculating particle collisions, Professor Bray’s team have extensively used Pawsey Supercomputing Centre. With the help of the Magnus Supercomputer, one of the southern hemisphere’s most powerful public research supercomputers, the team have been able to accurately calculate collisions.
“We’ve used Pawsey for everything. We’ve been utilising that supercomputer centre at its capacity throughout its existence. As the centre became more powerful it opened up more possibilities. Now we’ve been doing molecular work over the past five years or so,” said Professor Bray.
Professor Bray’s team are still working on simple collisions, involving atoms or diatomic particles. The team are able to map more complex molecules, but the complexity of these collisions reduce result accuracy.
“With unlimited computing power the sky’s the limit. We could do calculations with much larger molecules, like biological ones. But with what we have at the moment, it’s important to decide how we’re going to use those resources. The niche that we have chosen is to do whatever we do well or don’t do it at all.”
“It used to be, 20 years ago, astronomers would say if we could get data to within an order of magnitude or a factor of two that would be brilliant. That’s not true anymore,” said Professor Bray.
The team’s work has applications across many fields, from the lighting and television engineering industry, to some of the most ground-breaking science in the world.
Particle collision calculations made by Professor Bray’s team are currently used in planning the International Thermonuclear Experimental Reactor.
Much like a miniature version of the sun, it will be the world’s first fusion reactor to produce a surplus of power and relies on the interactions of hydrogen atoms. Professor Bray’s work is also used in proton therapy, a new form of cancer therapy used to cure child brain cancer. “You bombard the body with protons at the spot where the tumour is. To be able to do that the energy and direction needed for the protons to reach that spot must be known. So you can destroy the tumour without the body damage usually associated with X-ray radiation,” said Professor Bray.
Most frequently, Professor Bray’s work is used in astronomy. By analysing the unique signature of protons in space using satellites and observatories, particle collision calculations can tell astronomers what supernovae and solar winds are made of. Despite the broad utility of Professor Bray’s work, he insists when the research into particle collisions began many years ago, there was no specific outcome for the research in mind.
It was simply curiosity about how the universe worked at the atomic level. “Is our research geared towards a specific application? Not really. That’s not how we work. We work on solving problems. The fact they have applications is fantastic and it proves why we need to be working on these problems. But we don’t know where these applications will be until we do the research,” said Professor Bray. “We know that certain problems deserve solving, even if we don’t know what applications the solutions will have. It’s also a feedback mechanism. When people know the solution they then wonder where it can be applied. That’s why we work together with everybody.”