US scientists identify robust new telecom-ready silicon quantum qubit

US scientists at UC Santa Barbara, collaborating with Brookhaven National Laboratory’s Co-design Center for Quantum Advantage, have discovered a new silicon-based qubit called the CN center, which consists of a carbon-nitrogen defect embedded directly into silicon. This qubit is notable for being robust and telecom-ready, emitting light at telecom wavelengths and exhibiting long-lived quantum states. Unlike the previously studied T center—which contains hydrogen and suffers from fabrication challenges due to hydrogen’s mobility—the CN center replaces hydrogen with nitrogen, resulting in enhanced structural stability and manufacturability using existing silicon photonics platforms. The CN center preserves the advantageous electronic and optical properties of the T center but avoids the drawbacks associated with hydrogen diffusion during chip processing, making it a promising candidate for scalable, mass-producible quantum devices. This discovery represents a significant step toward integrating quantum light sources into silicon-based technologies, potentially accelerating the development of advanced quantum processors and photonic chips using the same materials and fabrication tools as current semiconductor electronics. The findings were supported