CAREER: Coherent Control, Measurement, and Entanglement of Single T-Center Qubits

A quantum network could be used to improve security and future economic growth by enabling larger quantum computers, and by supporting fundamentally new types of communication. However, identifying specific components and systems with all the requisite optical and quantum properties for building a quantum network remains challenging. One promising platform for developing this technology uses atomic scale defects in crystalline materials. A relatively novel solid-state defect to explore is known as a T center defect in silicon. This research project aims to analyze the optical and spin properties of single T centers and develop quantum optics methods to enable their efficient manipulation and control, towards the realization of T-center-based quantum network nodes. The knowledge gained about the fundamental properties of T centers and the methods developed to interface with them will help to push forward the scientific frontier of solid-state spin-based quantum information processing research, as well as the technical advancement of quantum networking. The project also aims to train the workforce for the future quantum industry, by incorporating comprehensive education and research components, such as the new quantum curriculum, capstone research projects and summer REUs, and for graduate and undergraduate students. The team will also organize outreach activities to local high school students to invigorate their interest in quantum science. Optically interfaced solid-state spins provide a promising platform for quantum information processing and quantum networking applications. Furthermore, manipulating solid-state spins with light at telecom wavelengths will facilitate large-scale quantum networks that leverage existing telecommunication fiber networks. This project will explore how T centers in silicon can be controlled with telecom band optical transitions and demonstrate long spin coherence times for various quantum networking protocols and applications. This team will analyze optical and spin properties of single T centers and develop new methods for their coherent control, measurement, and entanglement generation. Central to this effort is integrating single T centers with low-loss silicon photonic cavities to enhance light-matter interactions. The group will employ cavity-assisted interactions to explore high-fidelity spin readout and T-center spin-spin interactions, as well as spin-photon entanglement generation. The work will lay a foundation for using T centers in silicon to build telecom quantum network nodes and future quantum repeaters for long-distance quantum networks. Methods developed in this project will impact research fields including quantum optics, quantum information, quantum communication, and materials science. The project is integrated with education components, which will allow students to gain advanced and interdisciplinary training in photonics, materials engineering, and quantum science. 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.