This award supports a multidisciplinary international collaboration for research and education addressing the challenge of producing, controlling, and measuring quantum entanglement. Entanglement is one of the most profound concepts to emerge from quantum mechanics, giving rise to correlations between the states of physical systems, even widely separated ones. Entanglement and its preservation underlie new technologies such as quantum sensing, quantum repeaters, and quantum computation. This collaboration includes both experimental and theoretical work, with researchers at Oxford University and Heriot-Watt University in the United Kingdom, and Princeton University. The long-term goal of the project is to understand how transient electron spins can be used to mediate quantum entanglement between multiple nuclear spins. The work addresses long-standing questions related to spin decoherence in various condensed matter systems, and explores new uncharted territory concerning the evolution and destruction of entangled states. Both carbon- and silicon-based materials and devices will be studied, using Electron Paramagnetic Resonance (EPR), Electron-Nuclear Double Resonance (ENDOR), and Electrically Detected Magnetic Resonance (EDMR) techniques. After electron spins are entangled with nuclear spins in their immediate vicinity, the electrons will be moved to where they can interact with a new set of nuclei. It may be possible to entangle widely separated nuclear spins with these methods. Questions concerning the loss of coherence associated with the removal and reintroduction of the electrons will be addressed, as well as the possible loss of coherence during the electrons' motion.
This project builds upon a highly successful though largely informal collaboration amongst the senior researchers which has existed for several years. The work directly addresses key questions at the interface between fundamental and applied science, with important immediate applications in the emerging field of quantum information. The students associated with this project will benefit from the seamless flow of ideas, information, and people between the partner institutions in the network. Frequent exchange of students and postdocs between the groups at Oxford and Heriot-Watt with the Princeton group are planned. These exchanges will allow the researchers to take advantage of complementary experimental equipment and theoretical expertise at the partner institutions. It is this kind of cross-disciplinary international training which will be important for a new generation of device engineers and scientists.