Simulation of photochemical reactions with near-term quantum computers

Photochemistry involves the excitation of electrons in a molecule interacting with light, and the reactions that result from the excited molecule. It is extremely difficult to simulate with conventional computers due to strong coupling between atomic vibrations and electronic states. As a result, our understanding of photochemistry lags behind that of reactions on the ground electronic state. This program will solve the simulation problem by developing novel approaches to simulate photochemical reactions using quantum computers. It will use the advantages and limitations of different types of quantum computers in order to best study effects that are beyond the abilities of classical computers. Through collaborations with experimental quantum technology research groups, this program will demonstrate a practical advantage for quantum computation in quantum chemistry, and has the potential to lead a paradigm shift in quantum chemistry research. This program consists of three principal aims. The first is the development of a model of photchemical dynamics which uses only local information, such as atom types and connectivities. It will enable the simulation of large-scale systems on quantum computers which otherwise require expensive pre-calculation for each molecule. The second aim is to develop an analog quantum computing technique for the coupled dynamics of electrons and nuclei, meaning a technique which uses a controllable quantum system to mimic the behaviour and properties of electrons and nuclei in molecules. It will enable the accurate simulation of quantum effects in photochemistry without resorting to common approximations necessary for classical computers. The final aim is the development of universal, digital quantum computing algorithms for the simulation of fully coupled electrons and nuclei. This approach will allow for applications to be scaled up as quantum technology develops, providing an equal treatment of ground-state chemistry and photochemistry. This program will fully fund the research and training of four graduate students. It will provide students with the opportunity to work on and develop research projects in the rapidly evolving field of quantum computing. Students will gain experience through collaborations with world-class experimental facilities, and their research will enable them to pursue careers in academia or in the growing quantum industry.