Cartagena Engineers Quantum Measure Critical Point for Self-Sustained Magnetometer

Researchers at the Universidad Politécnica de Cartagena have moved beyond standard precision sensing by deliberately inducing instability in a nitrogen-vacancy (NV) ensemble magnetometer. The team drove the frequency-modulation (FM) locked magnetometer through a bifurcation by raising the software loop gain, transforming it into a self-sustained oscillator. This shift means the magnetometer’s internal feedback loop generates a continuous signal, rather than relying on an external stimulus. The work identifies a measurable threshold linked to the ratio of the magnetometer’s transduction slope at calibration to its present value, and reports measurements showing sub-threshold critical fluctuations aligning with predicted divergence. Researchers…