Quantum Sensors Illuminate Elusive Neutrino Interactions
Researchers at CEA-List are pioneering the use of quantum sensors to detect the subtle magnetic moments of neutrinos, a fundamental particle that rarely interacts with matter. This novel approach could provide a new pathway to probe neutrino properties and test the limits of the Standard Model of particle physics.
Neutrinos, often called "ghost particles," pass through most matter undetected. Their extremely weak interaction makes direct measurement of their magnetic moment—a key quantum property—exceptionally challenging with conventional detectors. The CEA-List team is developing sensors based on nitrogen-vacancy (NV) centers in diamond, a solid-state quantum technology. These NV centers are atomic-scale defects whose quantum spin states are highly sensitive to minute magnetic fields.
The experimental setup involves placing a diamond sensor containing a high density of NV centers near a powerful neutrino source, such as a nuclear reactor. As neutrinos stream through the diamond, the infinitesimal magnetic field associated with a potential neutrino magnetic moment would interact with the sensor's electron spins. This interaction is read out by monitoring changes in the NV centers' fluorescence under laser excitation—a technique known as optically detected magnetic resonance (ODMR).
Preliminary analyses indicate this method could achieve a magnetic moment sensitivity several orders of magnitude better than current experimental limits set by large-scale observatories like Borexino. Success would not only measure a fundamental neutrino parameter but could also shed light on physics beyond the Standard Model, including potential connections to dark matter. The research represents a significant convergence of quantum sensing technology and fundamental particle physics.