In theory, quantum mechanics should offer perfect understanding of some of the most interesting events in chemistry–for example, the behavior of excited electrons, which controls such things as photosynthesis in plants. In practice, however, the necessary calculations are far too difficult for even the most powerful computers. So approximations must be made, especially when larger molecules such as proteins are involved.
Alán Aspuru-Guzik, a theoretical chemist at Harvard, is developing methods that could one day do away with the need for approximations altogether–and lead to better drugs or solar cells.
He has created an algorithm that allows quantum computers to simulate chemistry with a level of accuracy that traditional computers will never be able to match. Although quantum computers are not yet powerful enough to simulate the behavior of large molecules, Aspuru-Guzik and collaborators in Australia, working with an experimental quantum computer, successfully used the algorithm to compute the energy of the hydrogen molecule.
Aspuru-Guzik is also probing the quantum effects at the heart of photosynthesis in the hopes of developing cheaper and more efficient organic photovoltaics.–Neil Savage