Title: A platform for future development and application of the ONETEP software
Funder: Engineering and Physical Sciences Research Council

Abstract: Computer simulations play a growing role in our society e.g. flight simulators allow pilots to be trained more cheaply and safely than in the air. In science and technology, computer simulation is a powerful tool for understanding or even predicting complex processes in real materials. Simulations are often used alongside conventional experiments, but they can also be used in situations where experiments would be too expensive or even impossible to perform e.g. when studying materials in extreme conditions such as the high temperatures and pressures found in the Earth's core. The turn of the last century saw the start of a scientific revolution with the discovery of quantum mechanics (QM), a theory that describes the world on the atomic scale with astonishing accuracy, and thus provides the foundation for all of low-energy physics, chemistry and biology. In principle at least, quantum mechanics underlies the microelectronics, chemical and pharamaceutical industries upon which our society relies today. The challenge is that the equations of QM are very complicated. Even on the fastest computers it is only possible to solve them exactly for small molecules, whereas the systems of interest to scientists today contain many thousands. Even the rapid and relentless progress of computer technology cannot overcome this because of the scaling of the problem. The work needed to complete a task usually increases with its size e.g. the time taken to mow a lawn is proportional to its area: double the size of the garden and it takes twice as long. This is an example of linear scaling, but the effort to do many tasks increases more rapidly. Arranging a hand in a game of cards usually scales as the square of the number of objects involved: triple the number of cards and it takes nine (three squared) times as long. Some are even worse e.g. solving the travelling salesman problem to find the quickest route which visits a given set of locations. Adding one extra location doubles the amount of time to solve the problem. If three locations can be done in one minute, four will take two minutes, and five will take four minutes. Just 22 will take a whole year! Solving QM exactly scales like this when increasing the number of atoms being simulated. However in the 1960s a leap forward was made with the discovery of density-functional theory (DFT), for which the Nobel Prize was awarded in 1998. The remarkable result of DFT is that the physical properties of the whole system (the answers to the questions we want to ask) can in principle be calculated in a time that scales linearly with the number of atoms The research proposed here relates to one of the leading pieces of software for performing linear-scaling DFT calculations in the world. This ONETEP code has been demonstrated on systems containing up to 30,000 atoms so far. This method will expand the scope and scale of QM simulations across a wide range of fields. The problems we intend to address using this Platform grant include: - giving insight into the design of new drugs by simulating the interactions between proteins - designing new materials for solar energy conversion and storage - studying the properties of nanoparticles as catalysts for chemical reactions - understanding the microscopic processes associated with friction that cause machinery to wear out Our vision is to create a virtual laboratory which uses ONETEP as one of a family of techniques to simulate the results of real experiments e.g. how a material absorbs light. The virtual lab gives total control: you can change the arrangement of atoms in a material or molecule and see the effect. The virtual lab will never replace the real one, but it promises to be a powerful tool alongside it.


Research activity codes: 1.4 METHODOLOGIES AND MEASUREMENTS
Health categories: GENERIC HEALTH RELEVANCE