Exploring Mesoscale Interactions in Color Center Clusters

This project explores new strategies for connecting quantum bits (qubits) based on atomic-scale defects, or "color centers", in diamond. These defects can be individually manipulated using light and are promising candidates for future quantum technologies. However, building larger systems of such qubits remains a major challenge, primarily because magnetic interactions between them are extremely short-ranged. This research investigates whether long-range electric interactions, made possible by the special structure of certain color centers, could serve as an alternative pathway to link qubits. By doing so, the project aims to uncover new mechanisms for controlling quantum states across distances greater than currently possible. If successful, this work could lead to more scalable solid-state platforms for quantum computing, sensing, and secure communication, advancing U.S. leadership in the growing field of quantum information science. The project also provides students with hands-on training in quantum science, experimental physics, and advanced materials research, preparing them for future careers in both academia and industry. Technically, the project focuses on three complementary approaches using color centers in diamond, particularly the nitrogen-vacancy (NV) and silicon-vacancy (SiV) centers. The first approach targets low-temperature control of orbital states in neutral NV centers to probe electric-dipole interactions within tightly spaced clusters. The second explores whether highly excited Rydberg-like states can form around these defects, enabling a type of “blockade” effect where one excited qubit prevents nearby excitations — a powerful tool for mediating interactions at the micron scale. The third investigates the possibility of controlled spin-based charge transfer between defects, using resonant photoexcitation. Together, these efforts aim to establish foundational understanding of new coupling mechanisms for solid-state qubits, expanding the scientific toolkit for building coherent, controllable quantum networks. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.