In quantum sensing, researchers harness atomic-scale quantum systems to revolutionize measurements of electromagnetic fields, rotation, acceleration, and distance. These systems offer precision far beyond classical sensors and hold promise for groundbreaking applications such as detailed brain imaging and highly accurate air traffic control systems.
A notable avenue in quantum sensing involves leveraging microscopic defects within diamonds to create qubits, the fundamental units of quantum devices. Researchers at Massachusetts Institute of Technology (MIT) and collaborating institutions have developed a groundbreaking technique to identify and manipulate a larger number of these defects, paving the way for enhanced quantum sensing capabilities.
Central to their method is using a specific protocol of microwave pulses to detect and extend control to additional defects known as dark spins, which cannot be directly observed with a laser. By establishing a network of connected spins, researchers can locate and control these dark spins, thereby expanding the system of qubits.
The technique involves coupling a central defect, such as the nitrogen-vacancy (NV) center, with a nearby dark spin, then utilizing this dark spin as a probe to identify and control a more distant spin. This process can be iterated to create longer chains of spins, forming larger quantum registers and enhancing the performance of quantum sensors.
Despite the challenges of working with these microscopic systems, researchers optimized their protocol to send microwave pulses precisely, enabling effective identification and control of second-layer spins. While successfully demonstrated a three-spin chain, they anticipate scaling their method to even greater complexities, potentially accessing hundreds of qubits.
Looking ahead, researchers aim to refine their technique further to probe additional electronic spins and explore diverse types of defects for qubit formation. Supported by organizations like the U.S. National Science Foundation and the Canada First Research Excellence Fund, this research represents a significant stride towards realizing the transformative potential of quantum sensing technologies.
