ICTP has recently joined the race for fast computers. It's a decision likely to help keep researchers throughout the Centre on track.

Fast Computers,
Real Phenomena

No group is more amazed by the simplicity and beauty of the fundamental laws of physics than theoretical physicists themselves, particularly when their own fields of study shed unexpected, yet revealing, light on the variety and complexity of the laws' manifestation in nature.
How can Schroedinger's equation, a tidy example of mathematical synthesis, describe the messy arrangement of atoms that compose the paper that this article is written on? And how can the three Navier-Stokes equations, which can easily fit on the back of an envelope, reveal a great deal about the aerodynamics of flight?
Equally interestingly, what is it about the laws of physics that enable scientists to predict such physical phenomena as climate dynamics and the creation of such materials as superhard solids from the bottom up (or perhaps more accurately from the top down)--that is, from the basic laws of classical and quantum mechanics.
Using computers to solve the fundamental laws of physics and provide answers to such complex questions has a long history, which began in the 1940s with the pioneering and visionary work of John von Neumann at Los Alamos National Laboratory in the USA.
Luckily, human endeavour in this field has been paralleled by breathtaking increases in the speed and memory of computers. As a result, such simple problems as a computer synchronising the rinse-and-spin cycle on a washing machine, which could only be solved on rudimentary punch-card machines 30 years ago, now require just a tiny portion of a computer chip for their calculation.
Even more startling to consider is the fact that new computer processors for desktop PCs experience a doubling of capacity every 18 months, according to Moore's celebrated law, named after Gordon Moore, the famed co-founder of Intel, who first presented this insight in 1965.
"Simulating the behaviour of matter at the atomistic scale by solving Schroedinger's equation is one activity among many in the very active and prolific field of computational physics, which has received a tremendous boost over the past 20 years due to a rapid increase of computer capabilities," says Sandro Scandolo, one of the newest members of the ICTP condensed matter physics group. "We can now determine with a high degree of accuracy the electronic and mechanical properties of solids and in some cases find interesting surprises."

Sandro Scandolo

Three years ago, for example, a group of scientists at the International School for Advanced Studies (SISSA) that included Scandolo and Erio Tosatti, currently ICTP's acting deputy director, discovered that simulations of the compression of carbon dioxide to one million atmospheres transformed this inert and innocent gas into superhard solid material. Their findings immediately prompted a global experimental search for this new material, which was synthesized the same year following the same route--extreme compression--by scientists at Lawrence Livermore National Laboratory, USA.
Climate prediction is another field where computer simulations are extremely helpful.
"Numerical models of the climate system, including the atmosphere, oceans and ice caps, have developed to a stage that allows us to understand the interactions between 'natural' climate variability and the climatic impacts of human activities," says Franco Molteni, staff member in the Physics of Weather and Climate group. "Indeed, simulations developed by the Intergovernmental Panel on Climate Change (IPCC) projecting future climate scenarios have been based on numerical models created by some of the most powerful supercomputers in the world."
But computer simulations are not just an indispensable tool for high-level scientific research. They have also become a valuable teaching instrument in universities and research centres in both the North and the South.
"Computer literacy in most developing countries is growing at an extremely rapid rate, possibly faster than literacy in the basic sciences," says Scandolo, "thanks to the internet and the increasing availability of PCs with high performance and low cost. We need to take advantage of this global market trend and turn it into an opportunity to foster education in physics and other basic sciences in developing countries."
In fact, the improvements in hardware performance are so rapid that the performance of a $10,000 top-of-the-line processor today can be replicated in two-years' time by a $1,000 processor in a desktop PC.
Two years are an extremely brief period on the time-scale of scientific progress. This means that high-quality scientific achievements in computationally oriented disciplines can be obtained with financial investments that are affordable for institutions in less developed countries. Put another way, money and, consequently, time are not the obstacles they used to be for scientists who draw on computer-driven calculations for their research.
Equally encouraging, the rapid narrowing of the performance/cost ratio for PCs has brought a welcome paradigm shift in the design of high-performance machines for scientific computing.
In the past, high-performance computers had to be tailored to the needs of the scientific community. The fastest computers in the 1970s were constructed explicitly for scientific applications. Nowadays, parallel computers based on dozens of standard PC processors, assembled and interconnected with a fast network, provide computational power that exceeds by orders of magnitude that of the fastest machines available in the 1970s, satisfying the needs of banks, insurance companies and scientific institutions alike.
ICTP has taken advantage of this 'building block' approach by recently acquiring a cluster of 80 PC processors. This cluster will dramatically boost in-house computational research capabilities--a turn of events especially welcomed by staff and visiting scientists in the fields of condensed matter physics and physics of weather and climate.

Franco Molteni

"We are excited by this opportunity," says Molteni, "which will give us the ability to test climate simulations on a time scale of up to 100 years. Also, by running several simulations based on a variety of conditions, we can distinguish the effects of the chaotic nature of climate dynamics from the 'greenhouse' gas and aerosol effects caused by human activities."
"On another research front, a parallel computer with such a large number of processors will finally allow us to test whether water becomes metallic at the extreme conditions found in the interiors of Uranus and Neptune, a speculation that we put forward a few years ago, but that is still
awaiting confirmation from simulations on a larger scale,"
Scandolo adds.
Ralph Gebauer, also with the Condensed Matter Physics group, has a different but equally enticing vision of future accomplishment: "I'd like to understand the physical mechanisms that control transport and dissipation in molecular junctions, the building blocks of the future generations of processors." In other words, Gebauer would like to tap the capabilities of today's computers to lay the theoretical groundwork for even faster computers in the future.

ICTP computer bank

Scientific research is often like a marathon--with the winners usually those who are intellectually fit enough to stay the course. But progress in this marathon requires the ability to win sprints as well, and increasingly fast computers provide the 'data track' you need to stay in the day-by-day competition.
Now, with the recent arrival of in-house fast computers, ICTP scientists have found themselves in the enviable position of being able to compete in both the short- and long-distance runs that increasingly characterise the nature of competition in their fields. Such an environment has positive implications not just for global science but for our global community
as well.

Back to Contents Forward to Features

Home